#include <iostream>
#include <cstdio>

using namespace std;

int main() {

	int ans = 0;
	int ret, tmp;

	for (int bit = 30; bit >= 0; bit--) {
		tmp = ans + (1 << bit);
		cout << "? " << tmp << endl;
		cin >> ret;

		if (ret == 1) {
			ans = tmp;
		}
	}

	cout << "! " << ans << endl;
	return 0;
}