#include <bits/stdc++.h>
#define rep(i,n) for(int i=0;i<(int)(n);i++)
using namespace std;
using ll = long long ;
using P = pair<int,int> ;
using pll = pair<long long,long long>;
constexpr int INF = 1e9;
constexpr long long LINF = 1e17;
constexpr int MOD = 1000000007;
constexpr double PI = 3.14159265358979323846;

int main(){
    string s,t;
    int l = 0,r = 1000;
    while(r-l>1){
        int m = (l+r)/2;
        cout << "? " << m << endl << flush;
        cin >> s;
        if(s=="out"){
            cout << "? " << m+1 << endl << flush;
            cin >> t;
            if(t=="out"){
                r = m;
            }else{
                l = m;
            }
        }else{
            l = m;
        }
    }
    cout << "? " << l << endl << flush;
    cin >> s;
    if(s=="out"){
        cout << "! " << l-1 << endl << flush;
    }else{
        cout << "! " << l << endl;
    }
    return 0;
}