#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef long double ld;
#define REP(i, n) for (int i = 0; i < (n); ++i)
#define REPR(i, n) for (int i = n - 1; i >= 0; --i)
#define FOR(i, m, n) for (int i = m; i < n; ++i)
#define FORR(i, m, n) for (int i = m; i >= n; --i)
#define ALL(v) (v).begin(),(v).end()
template<class T>bool chmax(T &a, const T &b) { if (a<b) { a=b; return 1; } return 0; }
template<class T>bool chmin(T &a, const T &b) { if (b<a) { a=b; return 1; } return 0; }
const ll INF=1LL<<60;
const int inf=(1<<30)-1;
const int mod=998244353;
int dx[8]={1,0,-1,0,-1,-1,1,1};
int dy[8]={0,1,0,-1,-1,1,-1,1};
int main(){
    cin.tie(0);
    ios::sync_with_stdio(false);
    int l=0,r=1001;
    while(r-l>1){
        int mid=(l+r)/2;
        cout << "? " << mid << endl;
        string res1,res2;
        cin >> res1;
        cout << "? " << mid+1 << endl;
        cin >> res2;
        if(res1=="safe"&&res2=="safe"){
            l=mid+1;
        }
        else if(res1=="safe"&&res2=="out"){
            l=mid;
        }
        else if(res1=="out"&&res2=="safe"){
            l=mid+1;
        }
        else{
            r=mid;
        }
    }
    cout << "! " << l << endl;
}