in how many territories were the wars fought where 4 . 7 /50 mark 3 were used ?
SELECT DISTINCT COUNT attr_open var_uri attr_close where brack_open dbr_4.7%22/50_Mark_3_ attr_open Armstrong attr_close dbo_usedInWar var_x sep_dot var_x dbo_territory var_uri sep_dot var_x a dbo_MilitaryConflict brack_close