CREATE TABLE table_21422977_2 (ministers VARCHAR, cabinet__nickname_ VARCHAR)

How many ministers are there when the cabinet (nickname) is Steingr mur Hermannsson III?
SELECT ministers FROM table_21422977_2 WHERE cabinet__nickname_ = "Steingrímur Hermannsson III"
SELECT "ministers" FROM "table_21422977_2" WHERE "Steingrímur Hermannsson III" = "cabinet__nickname_"