#include <iostream>
#include <vector>
#include <string>
#include <algorithm>
#include <cmath>

using namespace std;

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    cout << "? 0" << endl;
    short j, i;
    cin >> j;
    cout << "? " << j << endl;
    cin >> i;
    if(i)
        cout << "! " << -j << endl;
    else
        cout << "! " << j << endl;
}