l = 1
r = 1001
while r - l > 1:
    m = (l + r) // 2
    print("? {}".format(m))
    s = input()
    if s == "safe":
        l = m
        continue
    print("? {}".format(m - 1))
    s = input()
    if s == "safe":
        l = m - 1
    else:
        r = m - 1

print("! {}".format(l))