#include <bits/stdc++.h>
#define rep(i,n) for (int i = 0; i < (int)(n); i ++)
#define irep(i,n) for (int i = (int)(n) - 1;i >= 0;--i)
using namespace std;
using ll = long long;
using PL = pair<ll,ll>;
using P = pair<int,int>;
constexpr int INF = 1000000000;
constexpr long long HINF = 1000000000000000;
constexpr long long MOD = 1000000007;// = 998244353;
constexpr double EPS = 1e-4;
constexpr double PI = 3.14159265358979;

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

int main() {
    int l = 0,r = 1001;
    while (r - l > 1) {
        int m = (r + l)/2;
        if (ask(m)) l = m;
        else r = m;
    }
    while (!ask(l)) --l;
    cout << "! " << l << '\n'; 
    return 0;
}