def ask(a):
    print("? " + str(a))
    ans = input()
    if ans == "safe":
        return True
    else:
        return False

left, right = 1, 1000
while right - left > 1:
    mid = (left + right) // 2
    ans1 = ask(mid)
    ans2 = ask(mid + 1)
    if not ans1 and not ans2:
        right = mid
    elif ans2:
        left = mid + 1
    elif ans1:
        left = mid
print("! " + str(left))