#define _USE_MATH_DEFINES
#include  <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
#include <string>
#include<math.h>
#include<iomanip>
#include<stdio.h>
#include <stdlib.h>
#include<stdio.h>
#include <queue>
#include<map>
#include <fstream>
#include <sstream>
#include<set>
#include<stack>
#include<time.h>
#include <sys/types.h>
#include <tuple>
#include <numeric>
#include <iterator>
#include <atcoder/all>
#include <bits/stdc++.h>

#define rep(i,n) for (int i = 0; i < (n); ++i)
using namespace atcoder;
using namespace std;
typedef long long int ll;
typedef modint998244353 mint;




ll gcd(ll a, ll b) {
    if (a < b)swap(a, b);
    if (b == 0)return a;

    return gcd(b, a % b);
}
int lcm(int a, int b) {
    return a * b / gcd(a, b);
}

/*
解説動画参考
解説ブログ参考
https://blog.hamayanhamayan.com/entry/2020/05/02/002158
*/



int main()
{

    int Q;
    Q = 1;
    //cin >> Q;   
    
    
    while (Q--) {
        ll a = 1;
        ll b = 1e18 + 2;
        while (a + 1 < b) {
            ll m = (a + b) / 2;
            cout << "? " << m << endl;
            int x;
            cin >> x;
            if (!x)b = m;
            else a = m;
        }
        cout << "! " << a << endl;;
      
    }
    return 0;
}