l, r = 0, 1000
while r-l > 1:
	m = (l+r)//2
	print("? " + str(m), flush=True)
	x = input()
	print("? " + str(m+1), flush=True)
	y = input()
	if x == "safe" or y == "safe":
		l = m
	else:
		r = m
print("! " + str(l), flush=True)