from how many different institutes have the members of rank and insignia of the tanzanian armed forces graduated ?
SELECT DISTINCT COUNT attr_open var_uri attr_close where brack_open var_x dbo_militaryRank dbr_Rank_and_insignia_of_the_Tanzanian_Armed_Forces sep_dot var_x dbo_almaMater var_uri sep_dot var_uri a dbo_EducationalInstitution brack_close