in how many nations does national trust for places of historic interest or natural beauty own train stations ?
SELECT DISTINCT COUNT attr_open var_uri attr_close where brack_open var_x dbo_owningOrganisation dbr_National_Trust_for_Places_of_Historic_Interest_or_Natural_Beauty sep_dot var_x dbo_country var_uri sep_dot var_uri a dbo_Country brack_close