#include<bits/stdc++.h>

using namespace std;
using ll = long long;


int main()
{
    int lef = 0, rig = 1000; //k か k + 1のどちらかでは怒られが発生しないか? lef = ok
    string sm, lr;
    while(rig - lef > 1) {
        int mid = (lef + rig) / 2;
        cout << "? " << mid << endl; cin >> sm;
        cout << "? " <<mid+1<< endl; cin >> lr;
        ((sm == "safe" || lr == "safe") ? lef : rig) = mid;
    }
    cout << "? " << lef << endl; cin >> sm;
    cout << "! ";
    if(sm == "safe")cout << lef << endl;
    else cout << rig << endl;

}