#include "bits/stdc++.h"
using namespace std;
#define ll long long int
#define rep(i,n) for( int i = 0; i < n; i++ )
#define rrep(i,n) for( int i = n; i >= 0; i-- )
#define REP(i,s,t) for( int i = s; i <= t; i++ )
#define RREP(i,s,t) for( int i = s; i >= t; i-- )
#define dump(x)  cerr << #x << " = " << (x) << endl;
#define INF 2000000000
#define mod 1000000007
#define INF2 1000000000000000000


int main(void)
{
    cin.tie(0);
    ios::sync_with_stdio(false);
	int ok = 1,ng = 1000000001;
	while (abs(ok - ng) != 1) {
		int mid = (ng + ok) / 2;
		cout << '?' << " " << mid << endl << flush;
		bool f; cin >> f;
		if (f) ok = mid;
		else ng = mid;
	}
	cout << '!' << " " << ok << endl << flush;

    return 0;
}