CREATE TABLE table_204_587 (id DECIMAL, "drop ( s ) " TEXT, "multiplayer map ( s ) " TEXT, "spec ops mission ( s ) " TEXT, "face off map ( s ) " TEXT, "xbox 360 release date" TEXT, "playstation 3 release date" TEXT)

tell me the number of face off maps .
SELECT SUM("face off map(s)") FROM table_204_587
SELECT SUM("face off map(s)") FROM "table_204_587"