how many people have parterned with the person choroegraphed by sergei ponomarenko in the past ?
SELECT DISTINCT COUNT attr_open var_uri attr_close where brack_open var_x dbo_formerChoreographer dbr_Sergei_Ponomarenko sep_dot var_x dbo_formerPartner var_uri sep_dot var_uri a dbo_Person brack_close