print("? 100", flush=True)
c = int(input())
t = 1
if c == 0:
	print("! 100")
elif c < 0:
	while True:
		print("? 9", flush=True)
		c = int(input())
		if c == 0:
			print("!", t+9)
			break
		t += 1
else:
	left = 100
	right = 10**9-1
	while True:
		center = (left + right + 1)//2
		print("?", center, flush="True")
		c = int(input())
		if c == 0:
			print("!", center+t)
			break
		elif c > 0:
			left = center
			right -= 1
		else:
			right = center-2
			left -= 1
		t += 1