// Template
#include <bits/stdc++.h>
#define rep_override(x, y, z, name, ...) name
#define rep2(i, n) for (int i = 0; i < (n); ++i)
#define rep3(i, l, r) for (int i = (l); i < (r); ++i)
#define rep(...) rep_override(__VA_ARGS__, rep3, rep2)(__VA_ARGS__)
#define per(i, n) for (int i = (n) - 1; i >= 0; --i)
#define all(x) (x).begin(), (x).end()
using namespace std;
using ll = long long;
constexpr int inf = 1001001001;
constexpr ll INF = 3003003003003003003;
template <typename T> inline bool chmin(T& x, const T& y) {if (x > y) {x = y; return 1;} return 0;}
template <typename T> inline bool chmax(T& x, const T& y) {if (x < y) {x = y; return 1;} return 0;}
// struct IOSET {IOSET() {cin.tie(0); ios::sync_with_stdio(0); cout << fixed << setprecision(10);}} ioset;

// Main
int main() {
    auto query = [](int x) -> bool {
        string str1, str2;
        cout << "? " << x << endl;
        cin >> str1;
        cout << "? " << x + 1 << endl;
        cin >> str2;
        return str1 == "safe" || str2 == "safe";
    };
    
    int ok = -1, ng = 1000;
    
    while (ng - ok > 1) {
        int mid = (ng + ok) / 2;
        (query(mid) ? ok : ng) = mid;
    }
    
    cout << "! " << ok << endl;
    return 0;
}