#include <iostream>
#include <iomanip>
#include <algorithm>
#include <array>
#include <cassert>
#include <utility>
#include <vector>

char S[10];

bool ask(const int v, int& t){
    --t; std::cout << "? " << v << '\n'; std::cin >> S;
    return S[0] == 's';
}

int main(void){
    int ok = 0, ng = 1000;
    int ask_t = 25;
    while(ng - ok > 1){
        const int mid = (ok + ng) / 2;
        if(ask(mid, ask_t)) ok = mid;
        else{
            if(ask(mid + 1, ask_t)) ok = mid + 1;
            else ng = mid;
        }
        if(ask_t > 25) return 1;
    }
    std::cout << ok << '\n';    
    return 0;
}