#include <iostream>
#include <cstdio>

using namespace std;

int n_ask = 0;

int ask(int Y){
	cout << "? " << Y << endl;
	int res;
	cin >> res;
	n_ask++;
	return res;
}

int main() {
	int ret = ask(64);

	if (ret == 0) {
		cout << "? 64" << endl;
		return 0;
	}

	int n_bit = ret == 1 ? 31 : 6;
	int ans = 1 << n_bit;
	ans--;
	for (int i = n_bit - 1; i >= 0; i--) {
		int tmp = ans - (1 << i);
		ret = ask(tmp - n_ask);
		if (ret == 0) {
			ans = tmp;
			break;
		} else if (ret < 0) {
			ans = tmp;
		}
	}
	cout << "! " << ans << endl;
}