import sys
l, r = 0, 100000
while r - l > 1:
    m = (l + r) // 2
    print("?", m)
    res = input()
    print("?", m + 1)
    res2 = input()
    if res == res2 == "out":
        r = m
    else:
        l = m
    sys.stdout.flush()
print("!", l)