CREATE TABLE table_17749 ("Pos" FLOAT, "Manufacturer" TEXT, "Seasons" TEXT, "Starts" FLOAT, "Wins" FLOAT, "Sole supplier" FLOAT, "First win" TEXT, "Last win" TEXT, "Drivers" FLOAT, "Constr." FLOAT)

Name the number of constr with the first win at the 1978 brazilian grand prix
SELECT COUNT("Constr.") FROM table_17749 WHERE "First win" = '1978 Brazilian Grand Prix'
SELECT COUNT("Constr.") FROM "table_17749" WHERE "First win" = '1978 Brazilian Grand Prix'