#include <iostream>
#include <algorithm>
#include <map>
#include <set>
#include <queue>
#include <stack>
#include <numeric>
#include <bitset>
#include <cmath>

static const int MOD = 1000000007;
using ll = long long;
using u32 = unsigned;
using u64 = unsigned long long;
using namespace std;

template<class T> constexpr T INF = ::numeric_limits<T>::max()/32*15+208;

int ask(int x){
    cout << "? " << x << endl;
    string ret;
    cin >> ret;
    return ret == "safe";
}

void answer(int x){
    cout << "! " << x << endl;
    exit(0);
}

int main() {
    int ok = 0, ng = 10010;
    while(ng-ok > 1){
        int mid = (ok+ng)/2;
        int ret1 = ask(mid), ret2 = ask(mid+1);
        if(!ret1 && !ret2) ng = mid;
        else ok = (ret2 ? mid+1 : mid);
    }
    answer(ok);
    return 0;
}