#include <bits/stdc++.h>
using namespace std;

int main() {
    int l = 0,r = 1001;
    while (l+1 < r) {
        int mid = (l+r)/2;
        string a,b;
        cout << "? " << mid << endl;
        cin >> a;
        cout << "? " << mid+1 << endl;
        cin >> b;
        if(a == "out" && b == "out") {
            r = mid;
        }
        else if(b == "safe") {
            l = mid+1;
        }
        else{
            l = mid;
        }
    }
    cout << "! " << l << endl;
}