#include <bits/stdc++.h>
template<class T> inline bool chmin(T&a, T b){if(a > b){a = b; return true;}else{return false;}}
template<class T> inline bool chmax(T&a, T b){if(a < b){a = b; return true;}else{return false;}}
#define ll long long
#define double long double
#define rep(i,n) for(int i=0;i<(n);i++)
#define REP(i,n) for(int i=1;i<=(n);i++)
#define mod (ll)(1e9+7)
#define inf (ll)(3e18+7)
#define pi (double) acos(-1.0)
#define P pair<int,int>
#define PiP pair<ll,pair<ll,ll>>
#define all(x) x.begin(),x.end()
#define rall(x) x.rbegin(),x.rend()
using namespace std;

void query(int n){cout << "? " << n << endl; flush(cout);}

bool solve(int n){
    string s1, s2;
    query(n);
    cin >> s1;
    query(n+1);
    cin >> s2;
    int cnt = 0;
    cnt += (s1 == "safe");
    cnt += (s2 == "safe");
    if(cnt == 0)return false;
    return true;
}

int main(){
    ll ok = 0, ng = 1000;
    while(ng-ok > 1){
        int mid = (ok+ng)/2;
        if(solve(mid))ok = mid;
        else ng = mid;
    }
    string s;
    query(ok+1);
    cin >> s;
    if(s == "safe"){
        cout << "! " << ok+1 << endl;
        return 0;
    }
    cout << "! " << ok << endl;
}