#include <iostream>
using namespace std;
int main(){
    int mn = 0;
    int mx = 1001;
    while(mx-mn > 1){
        int ce = (mn+mx)/2;
        cout << "? " << ce << endl;
        string s;cin>>s;
        if(s == "safe"){
            mn = ce;
        }else{
            cout << "? " << ce+1 << endl;
            cin>>s;
            if(s == "safe"){
                mn = ce+1;
            }else{
                mx = ce;
            }
        }
        
    }
    cout << "! " << mn << endl;
}