#include <bits/stdc++.h>
#define rep(i,n) for(int i = 0; i < (n); ++i)
#define srep(i,s,t) for(int i = s; i < t; ++i)
#define drep(i,n) for(int i = (n)-1; i >= 0; --i)
using namespace std;
typedef long long int ll;
typedef pair<int,int> P;
#define yn {puts("Yes");}else{puts("No");}
#define MAX_N 200005

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