from itertools import count
from math import floor, sqrt


def is_angry(num: int) -> bool:
    print(f"? {num}", flush=True)
    ans = input()
    match ans:
        case "out":
            return True
        case "safe":
            return False
        case _:
            raise ValueError


def answer(num: int):
    print(f"! {num}", flush=True)


def calc_positive_divisors(num: int) -> list[int]:
    small_divisors = []
    large_divisors = []
    for n in range(1, floor(sqrt(num))+1):
        if num % n == 0:
            small_divisors.append(n)
            large_divisors.append(num//n)
    if small_divisors[-1] == large_divisors[-1]:
        large_divisors.pop()
    divisors = small_divisors + reversed(large_divisors)
    return divisors


def calc_prime_factorize(num: int) -> dict[int, int]:
    if num < 2:
        raise ValueError

    divisors = {}
    for divisor in count(2):
        if divisor ** 2 > num:
            if num != 1:
                divisors[num] = 1
            break
        while num % divisor == 0 and num != 1:
            try:
                divisors[divisor] += 1
            except KeyError:
                divisors[divisor] = 1
            num //= divisor

    return divisors


def main():
    minimum = 1
    maximum = 1000

    while (maximum - minimum) > 1:
        if is_angry((minimum+maximum) // 2):
            if is_angry((minimum+maximum) // 2 + 1):
                maximum = (minimum+maximum) // 2
            else:
                minimum = (minimum+maximum) // 2 + 2
        else:
            minimum = (minimum+maximum) // 2 - 1

    if minimum == maximum:
        answer(minimum-1)
        return
    if is_angry(minimum):
        answer(minimum-1)
        return
    answer(minimum)


if __name__ == "__main__":
    main()