res = []

lo, hi = 0, pow(10, 3)
for i in range(8):
    mi = (lo + hi) // 2
    ok = False
    for x in range(mi - 1, mi + 2):
        print(f"? {x}")
        if input() == "safe":
            ok = True
            res.append(x)
    if ok:
        lo = mi
    else:
        hi = mi - 1

print(f"! {max(res)}")