#include <bits/stdc++.h>
using namespace std;
using ll = long long;

ll n, k;

ll query(ll x)
{
	cout<<"? "<<x<<endl;
	std::cout << std::flush;
	ll res;
	cin>>res;
	return res;
}

void solve()
{
	ll r = 1e12 + 10;
	ll m = query(r);
	ll t = r - m;
	t *= 2;
	ll ans = query(t);
	cout<<"! "<<ans<<endl;
	std::cout << std::flush;
}

int main()
{
    int t = 1;
    //	cin>>t;
    while (t--)
    {
        solve();
    }
    return 0;
}