#include <cstdio>
#include <cstring>
#include <iostream>
#include <string>
#include <cmath>
#include <bitset>
#include <vector>
#include <map>
#include <set>
#include <queue>
#include <deque>
#include <algorithm>
#include <complex>
#include <unordered_map>
#include <unordered_set>
#include <random>
#include <cassert>
#include <fstream>
#include <utility>
#include <functional>
#include <time.h>
#include <stack>
#include <array>
#define popcount __builtin_popcount
using namespace std;
typedef long long int ll;
typedef pair<int, int> P;

int main()
{
    int l=0, r=1000;
    int cnt=0;
    while(r-l>1){
        int m=(l+r)/2;
        assert(cnt<25);
        cout<<"? "<<m<<endl;
        cnt++;
        string res; cin>>res;
        if(res=="safe"){
            l=m;
            continue;
        }
        assert(cnt<25);
        cout<<"? "<<m+1<<endl;
        cnt++;
        cin>>res;
        if(res=="safe") l=m+1;
        else r=m;
    }
    cout<<"! "<<l<<endl;
    return 0;
}