When did China begin constructing the third BeiDou system? [SEP] As of March 2016, 4 BDS-3 in-orbit validation satellites have been launched.
not_entailment entailment entailment entailment entailment entailment not_entailment not_entailment entailment entailment entailment entailment entailment not_entailment not_entailment entailment not_entailment entailment entailment entailment not_entailment entailment entailment not_entailment entailment not_entailment entailment entailment not_entailment not_entailment entailment entailment not_entailment not_entailment not_entailment entailment entailment entailment entailment entailment not_entailment entailment not_entailment entailment not_entailment not_entailment entailment not_entailment entailment entailment not_entailment not_entailment not_entailment not_entailment not_entailment entailment entailment not_entailment not_entailment entailment entailment not_entailment entailment entailment entailment entailment entailment not_entailment entailment entailment not_entailment not_entailment not_entailment not_entailment not_entailment not_entailment entailment not_entailment entailment entailment not_entailment entailment not_entailment not_entailment not_entailment not_entailment entailment entailment entailment not_entailment entailment entailment entailment not_entailment entailment not_entailment entailment entailment not_entailment entailment entailment not_entailment entailment entailment entailment not_entailment not_entailment not_entailment entailment entailment not_entailment entailment entailment entailment not_entailment not_entailment entailment entailment entailment not_entailment not_entailment not_entailment entailment entailment entailment entailment not_entailment not_entailment not_entailment entailment not_entailment not_entailment not_entailment entailment entailment entailment not_entailment entailment entailment entailment entailment entailment entailment not_entailment not_entailment not_entailment entailment entailment not_entailment not_entailment entailment not_entailment not_entailment entailment entailment entailment entailment entailment entailment entailment not_entailment not_entailment entailment entailment entailment not_entailment not_entailment entailment not_entailment entailment entailment not_entailment not_entailment not_entailment not_entailment not_entailment not_entailment entailment not_entailment not_entailment entailment not_entailment entailment entailment not_entailment entailment not_entailment not_entailment entailment entailment entailment not_entailment not_entailment entailment not_entailment entailment not_entailment entailment entailment not_entailment not_entailment not_entailment entailment not_entailment entailment not_entailment entailment entailment entailment not_entailment entailment entailment entailment entailment not_entailment entailment not_entailment entailment entailment not_entailment not_entailment not_entailment not_entailment entailment not_entailment not_entailment entailment not_entailment entailment not_entailment not_entailment entailment entailment not_entailment entailment entailment entailment not_entailment entailment entailment entailment entailment entailment not_entailment not_entailment entailment not_entailment not_entailment not_entailment not_entailment entailment not_entailment not_entailment not_entailment not_entailment entailment not_entailment not_entailment entailment not_entailment not_entailment entailment entailment not_entailment entailment entailment not_entailment not_entailment entailment not_entailment entailment entailment entailment entailment entailment entailment not_entailment not_entailment not_entailment entailment not_entailment entailment not_entailment not_entailment entailment entailment not_entailment not_entailment not_entailment entailment not_entailment not_entailment entailment entailment entailment entailment not_entailment not_entailment entailment entailment not_entailment not_entailment not_entailment not_entailment entailment not_entailment not_entailment entailment entailment entailment not_entailment entailment entailment not_entailment entailment entailment not_entailment entailment entailment entailment entailment entailment entailment entailment entailment not_entailment entailment not_entailment entailment not_entailment not_entailment not_entailment not_entailment entailment entailment not_entailment entailment entailment not_entailment entailment entailment entailment not_entailment not_entailment entailment entailment entailment entailment not_entailment not_entailment not_entailment entailment not_entailment not_entailment not_entailment entailment not_entailment not_entailment not_entailment not_entailment entailment entailment entailment not_entailment not_entailment not_entailment not_entailment not_entailment entailment not_entailment entailment entailment entailment entailment not_entailment not_entailment not_entailment not_entailment not_entailment entailment not_entailment not_entailment not_entailment not_entailment entailment not_entailment not_entailment not_entailment not_entailment entailment not_entailment entailment not_entailment not_entailment entailment entailment not_entailment not_entailment entailment entailment entailment not_entailment entailment entailment not_entailment entailment not_entailment not_entailment entailment not_entailment entailment not_entailment not_entailment not_entailment not_entailment entailment entailment entailment not_entailment not_entailment entailment entailment not_entailment entailment not_entailment entailment not_entailment entailment entailment entailment not_entailment not_entailment entailment entailment entailment not_entailment not_entailment entailment entailment not_entailment entailment entailment not_entailment entailment entailment not_entailment not_entailment entailment not_entailment not_entailment entailment not_entailment entailment entailment not_entailment entailment entailment entailment not_entailment not_entailment entailment entailment not_entailment not_entailment entailment entailment not_entailment entailment not_entailment entailment not_entailment entailment entailment not_entailment entailment entailment entailment entailment not_entailment entailment entailment entailment entailment not_entailment entailment entailment entailment not_entailment not_entailment entailment entailment entailment not_entailment entailment not_entailment not_entailment not_entailment entailment entailment entailment entailment entailment entailment entailment not_entailment not_entailment not_entailment not_entailment entailment not_entailment not_entailment not_entailment entailment entailment entailment not_entailment entailment not_entailment not_entailment entailment entailment not_entailment not_entailment entailment not_entailment not_entailment not_entailment entailment not_entailment not_entailment entailment not_entailment not_entailment entailment entailment entailment not_entailment entailment not_entailment entailment not_entailment entailment entailment not_entailment not_entailment entailment not_entailment entailment not_entailment entailment entailment entailment entailment not_entailment not_entailment not_entailment entailment not_entailment entailment entailment entailment entailment entailment entailment not_entailment not_entailment not_entailment entailment not_entailment entailment not_entailment entailment entailment entailment not_entailment not_entailment entailment not_entailment not_entailment not_entailment entailment entailment not_entailment not_entailment not_entailment entailment not_entailment not_entailment entailment not_entailment entailment entailment not_entailment not_entailment entailment not_entailment entailment entailment not_entailment not_entailment not_entailment entailment not_entailment not_entailment entailment not_entailment not_entailment entailment entailment not_entailment entailment not_entailment not_entailment not_entailment entailment not_entailment entailment not_entailment entailment not_entailment entailment not_entailment not_entailment not_entailment entailment not_entailment entailment entailment entailment entailment not_entailment not_entailment entailment not_entailment not_entailment not_entailment not_entailment not_entailment entailment not_entailment not_entailment entailment entailment entailment not_entailment not_entailment not_entailment not_entailment not_entailment entailment entailment not_entailment not_entailment not_entailment not_entailment not_entailment entailment entailment not_entailment not_entailment not_entailment not_entailment not_entailment not_entailment not_entailment not_entailment not_entailment not_entailment entailment not_entailment entailment not_entailment not_entailment entailment entailment not_entailment not_entailment not_entailment entailment not_entailment entailment not_entailment not_entailment entailment entailment entailment not_entailment entailment not_entailment not_entailment not_entailment not_entailment entailment not_entailment not_entailment not_entailment entailment entailment entailment entailment not_entailment not_entailment not_entailment entailment not_entailment entailment not_entailment entailment not_entailment not_entailment not_entailment not_entailment entailment not_entailment entailment entailment entailment entailment not_entailment not_entailment not_entailment entailment entailment entailment not_entailment not_entailment not_entailment not_entailment entailment not_entailment entailment not_entailment not_entailment not_entailment entailment entailment not_entailment entailment entailment entailment not_entailment entailment entailment entailment entailment not_entailment entailment not_entailment not_entailment entailment entailment entailment entailment not_entailment entailment entailment entailment not_entailment entailment entailment not_entailment not_entailment entailment entailment not_entailment not_entailment not_entailment not_entailment entailment not_entailment entailment not_entailment entailment entailment not_entailment not_entailment entailment not_entailment entailment entailment not_entailment not_entailment entailment entailment not_entailment entailment not_entailment entailment not_entailment not_entailment not_entailment not_entailment not_entailment entailment not_entailment entailment entailment not_entailment not_entailment entailment entailment not_entailment entailment not_entailment not_entailment entailment not_entailment not_entailment entailment entailment entailment not_entailment not_entailment not_entailment not_entailment not_entailment entailment entailment not_entailment entailment entailment not_entailment entailment entailment entailment entailment not_entailment entailment entailment entailment not_entailment not_entailment not_entailment entailment entailment not_entailment entailment not_entailment entailment entailment entailment not_entailment entailment not_entailment not_entailment not_entailment not_entailment entailment not_entailment entailment entailment entailment entailment entailment not_entailment not_entailment not_entailment entailment not_entailment not_entailment not_entailment not_entailment entailment entailment entailment not_entailment entailment entailment entailment not_entailment entailment entailment entailment entailment not_entailment not_entailment not_entailment entailment entailment entailment entailment entailment entailment entailment not_entailment entailment entailment not_entailment not_entailment not_entailment not_entailment not_entailment entailment entailment entailment not_entailment entailment entailment not_entailment not_entailment entailment not_entailment entailment not_entailment entailment not_entailment not_entailment entailment not_entailment entailment not_entailment entailment entailment not_entailment entailment entailment not_entailment not_entailment entailment entailment not_entailment entailment not_entailment not_entailment not_entailment not_entailment entailment not_entailment not_entailment entailment not_entailment entailment not_entailment entailment not_entailment not_entailment entailment entailment entailment not_entailment not_entailment not_entailment entailment not_entailment not_entailment not_entailment not_entailment not_entailment entailment not_entailment not_entailment entailment not_entailment entailment not_entailment entailment entailment entailment entailment entailment not_entailment not_entailment entailment entailment not_entailment not_entailment not_entailment not_entailment entailment not_entailment entailment entailment not_entailment entailment not_entailment entailment not_entailment not_entailment not_entailment not_entailment entailment not_entailment entailment entailment not_entailment entailment not_entailment not_entailment not_entailment entailment entailment not_entailment not_entailment not_entailment entailment not_entailment entailment not_entailment entailment not_entailment not_entailment entailment not_entailment not_entailment not_entailment entailment entailment not_entailment entailment entailment not_entailment entailment entailment entailment entailment not_entailment not_entailment entailment entailment not_entailment entailment not_entailment not_entailment not_entailment not_entailment entailment entailment not_entailment not_entailment entailment not_entailment not_entailment entailment not_entailment not_entailment not_entailment not_entailment not_entailment entailment not_entailment not_entailment entailment entailment not_entailment not_entailment entailment not_entailment not_entailment not_entailment not_entailment not_entailment not_entailment not_entailment not_entailment entailment entailment entailment not_entailment not_entailment not_entailment not_entailment not_entailment entailment not_entailment entailment entailment not_entailment entailment not_entailment not_entailment entailment entailment entailment not_entailment not_entailment entailment entailment not_entailment not_entailment not_entailment not_entailment not_entailment entailment not_entailment not_entailment entailment not_entailment not_entailment entailment not_entailment entailment not_entailment not_entailment not_entailment entailment not_entailment not_entailment entailment entailment not_entailment entailment not_entailment not_entailment entailment entailment entailment not_entailment entailment not_entailment entailment entailment entailment not_entailment entailment not_entailment entailment not_entailment not_entailment entailment not_entailment entailment entailment not_entailment entailment entailment not_entailment entailment not_entailment entailment not_entailment not_entailment not_entailment entailment not_entailment not_entailment not_entailment not_entailment entailment entailment not_entailment not_entailment entailment not_entailment entailment entailment not_entailment not_entailment entailment not_entailment not_entailment not_entailment entailment entailment entailment not_entailment entailment entailment entailment entailment not_entailment entailment not_entailment entailment entailment entailment not_entailment not_entailment not_entailment not_entailment entailment entailment not_entailment entailment entailment not_entailment not_entailment not_entailment entailment entailment entailment not_entailment entailment entailment not_entailment not_entailment entailment not_entailment not_entailment not_entailment not_entailment not_entailment entailment not_entailment not_entailment entailment not_entailment not_entailment not_entailment not_entailment not_entailment not_entailment not_entailment entailment not_entailment not_entailment entailment entailment not_entailment entailment not_entailment entailment entailment entailment not_entailment not_entailment not_entailment entailment not_entailment not_entailment not_entailment entailment entailment entailment not_entailment not_entailment entailment entailment not_entailment not_entailment not_entailment not_entailment not_entailment entailment not_entailment entailment not_entailment entailment entailment entailment entailment not_entailment entailment entailment entailment not_entailment entailment not_entailment not_entailment entailment not_entailment not_entailment entailment not_entailment not_entailment not_entailment entailment entailment not_entailment not_entailment entailment not_entailment entailment entailment entailment not_entailment entailment entailment entailment not_entailment entailment entailment entailment entailment not_entailment entailment not_entailment entailment entailment entailment entailment not_entailment entailment not_entailment entailment entailment entailment entailment not_entailment not_entailment entailment entailment not_entailment not_entailment entailment not_entailment entailment entailment not_entailment entailment entailment entailment not_entailment not_entailment not_entailment entailment not_entailment entailment not_entailment not_entailment entailment entailment entailment not_entailment not_entailment not_entailment entailment not_entailment entailment not_entailment entailment entailment not_entailment not_entailment not_entailment not_entailment not_entailment not_entailment not_entailment not_entailment entailment entailment not_entailment not_entailment entailment entailment entailment entailment not_entailment entailment entailment entailment not_entailment not_entailment not_entailment entailment entailment entailment entailment not_entailment not_entailment not_entailment entailment not_entailment entailment entailment entailment entailment entailment entailment not_entailment not_entailment entailment not_entailment not_entailment not_entailment not_entailment entailment entailment entailment entailment entailment entailment not_entailment entailment entailment not_entailment not_entailment not_entailment entailment not_entailment not_entailment not_entailment entailment entailment not_entailment not_entailment entailment entailment entailment not_entailment not_entailment entailment not_entailment not_entailment entailment entailment not_entailment not_entailment entailment not_entailment not_entailment entailment entailment entailment entailment entailment entailment not_entailment not_entailment entailment not_entailment entailment entailment entailment entailment not_entailment entailment not_entailment not_entailment not_entailment entailment not_entailment not_entailment entailment entailment entailment not_entailment entailment not_entailment not_entailment not_entailment entailment not_entailment entailment entailment not_entailment not_entailment entailment entailment not_entailment not_entailment entailment not_entailment entailment entailment entailment not_entailment not_entailment entailment entailment not_entailment entailment not_entailment not_entailment entailment not_entailment not_entailment not_entailment entailment not_entailment entailment not_entailment entailment not_entailment entailment not_entailment entailment not_entailment entailment entailment not_entailment not_entailment entailment not_entailment not_entailment not_entailment not_entailment entailment not_entailment not_entailment not_entailment entailment entailment not_entailment entailment entailment entailment entailment not_entailment not_entailment entailment entailment not_entailment entailment not_entailment entailment not_entailment not_entailment not_entailment entailment not_entailment not_entailment not_entailment not_entailment not_entailment not_entailment entailment not_entailment entailment entailment entailment not_entailment entailment not_entailment entailment not_entailment not_entailment entailment entailment not_entailment not_entailment entailment not_entailment entailment entailment not_entailment not_entailment not_entailment not_entailment entailment not_entailment not_entailment entailment entailment entailment entailment entailment not_entailment entailment entailment not_entailment entailment not_entailment not_entailment not_entailment not_entailment entailment not_entailment not_entailment not_entailment not_entailment not_entailment not_entailment not_entailment entailment entailment entailment entailment not_entailment not_entailment entailment not_entailment not_entailment not_entailment entailment not_entailment entailment not_entailment not_entailment not_entailment entailment not_entailment entailment not_entailment entailment not_entailment entailment not_entailment not_entailment not_entailment not_entailment entailment not_entailment not_entailment entailment not_entailment not_entailment not_entailment entailment entailment not_entailment not_entailment not_entailment not_entailment entailment entailment entailment entailment entailment entailment entailment not_entailment not_entailment not_entailment not_entailment not_entailment entailment entailment entailment entailment entailment not_entailment entailment not_entailment not_entailment entailment entailment entailment not_entailment not_entailment not_entailment not_entailment not_entailment entailment entailment not_entailment entailment entailment entailment entailment not_entailment entailment not_entailment entailment entailment not_entailment not_entailment entailment entailment entailment not_entailment not_entailment not_entailment not_entailment entailment entailment entailment not_entailment entailment not_entailment not_entailment entailment not_entailment not_entailment entailment entailment entailment not_entailment entailment not_entailment entailment entailment not_entailment entailment entailment not_entailment entailment entailment entailment entailment entailment entailment not_entailment entailment entailment entailment entailment entailment not_entailment not_entailment not_entailment not_entailment entailment entailment entailment entailment entailment entailment not_entailment not_entailment entailment not_entailment entailment not_entailment entailment entailment entailment not_entailment not_entailment entailment not_entailment entailment not_entailment entailment not_entailment entailment not_entailment entailment entailment entailment not_entailment entailment entailment entailment entailment entailment entailment entailment entailment not_entailment not_entailment not_entailment entailment entailment not_entailment not_entailment entailment not_entailment entailment entailment entailment entailment not_entailment not_entailment not_entailment entailment not_entailment entailment entailment not_entailment entailment not_entailment not_entailment entailment not_entailment entailment entailment entailment not_entailment not_entailment entailment not_entailment not_entailment entailment entailment entailment not_entailment entailment not_entailment not_entailment entailment not_entailment entailment not_entailment entailment not_entailment entailment entailment entailment not_entailment not_entailment entailment entailment not_entailment not_entailment entailment not_entailment not_entailment entailment not_entailment not_entailment not_entailment entailment not_entailment not_entailment not_entailment not_entailment entailment not_entailment not_entailment not_entailment not_entailment entailment entailment entailment entailment not_entailment entailment entailment not_entailment entailment entailment entailment not_entailment not_entailment entailment not_entailment not_entailment entailment not_entailment not_entailment not_entailment entailment entailment not_entailment not_entailment entailment not_entailment not_entailment entailment entailment not_entailment entailment entailment not_entailment not_entailment entailment entailment entailment not_entailment entailment entailment not_entailment not_entailment entailment entailment not_entailment entailment not_entailment not_entailment not_entailment entailment entailment entailment entailment entailment not_entailment entailment entailment not_entailment entailment not_entailment entailment entailment not_entailment not_entailment not_entailment not_entailment entailment entailment not_entailment not_entailment not_entailment not_entailment entailment entailment entailment not_entailment not_entailment entailment entailment not_entailment not_entailment entailment entailment not_entailment entailment entailment not_entailment not_entailment entailment not_entailment not_entailment not_entailment not_entailment entailment not_entailment entailment not_entailment not_entailment not_entailment not_entailment not_entailment entailment not_entailment not_entailment not_entailment entailment not_entailment not_entailment entailment not_entailment not_entailment not_entailment not_entailment entailment not_entailment not_entailment entailment not_entailment not_entailment not_entailment not_entailment not_entailment not_entailment entailment not_entailment not_entailment entailment not_entailment entailment not_entailment not_entailment entailment entailment not_entailment not_entailment not_entailment entailment entailment entailment entailment entailment not_entailment not_entailment not_entailment entailment entailment not_entailment entailment not_entailment entailment entailment not_entailment entailment entailment entailment entailment entailment not_entailment not_entailment not_entailment not_entailment entailment entailment not_entailment entailment entailment not_entailment not_entailment entailment entailment entailment not_entailment not_entailment not_entailment not_entailment entailment not_entailment not_entailment entailment entailment not_entailment not_entailment not_entailment not_entailment entailment not_entailment not_entailment entailment not_entailment entailment not_entailment entailment not_entailment not_entailment not_entailment not_entailment not_entailment entailment entailment entailment not_entailment not_entailment not_entailment entailment not_entailment entailment entailment not_entailment entailment entailment not_entailment not_entailment entailment entailment not_entailment entailment entailment not_entailment entailment not_entailment not_entailment not_entailment entailment not_entailment not_entailment not_entailment entailment entailment entailment not_entailment entailment entailment not_entailment not_entailment entailment not_entailment entailment not_entailment entailment not_entailment not_entailment not_entailment not_entailment not_entailment entailment not_entailment entailment entailment not_entailment not_entailment entailment not_entailment entailment entailment not_entailment entailment