(op = 0) || !(op = 0) && (op = 1) || !(op = 0) && !( op = 1) && (op = 2) || !(op = 0) && !(op = 1) && !(op = 2) && (op = 3) && !(y = 0) || !(op = 0) && !(op = 1) && !(op = 2) && !( op = 3) ;