#include <bits/stdc++.h>
using namespace std;
#define rep2(i,m,n) for (int i = (m); i < (n); ++i)
#define rep(i,n) rep2(i,0,n)
typedef long long int ll;
typedef long double ld;
typedef pair<int, int> P;
template<typename T> struct V : vector<T> { using vector<T>::vector; };
V() -> V<int>;
V(size_t) -> V<int>;
template<typename T> V(size_t, T) -> V<T>;
template<typename T> vector<T> make_vec(size_t n, T a) { return vector<T>(n, a); }
template<typename... Ts> auto make_vec(size_t n, Ts... ts) { return vector<decltype(make_vec(ts...))>(n, make_vec(ts...)); }
template<typename T> ostream &operator<<(ostream &os, const vector<T> &v) { for (auto &e : v) os << e << ' '; return os; }
struct fast_ios { fast_ios(){ cin.tie(nullptr); ios::sync_with_stdio(false); cout << fixed << setprecision(20); }; } fast_ios_;
template<typename T1,typename T2> inline void chmin(T1 &a,T2 b){if(a>b) a=b;}
template<typename T1,typename T2> inline void chmax(T1 &a,T2 b){if(a<b) a=b;}
const int INF = 1<<30;
const ll LINF = 1LL<<61;

int main()
{
    ll ok = 0, ng = 1001;
    while(abs(ok - ng) > 1)
    {
        ll mid = (ok + ng) / 2;
        bool f = true;
        cout << "? " << mid << endl;
        string x;
        cin >> x;
        if(x == "safe") f = true;
        else
        {
            cout << "? " << mid+1 << endl;
            string y;
            cin >> y;
            if(y == "safe") f = true;
            else f = false;
        }
        
        if(f) ok = mid;
        else ng = mid;
    }
    cout << "! " << ok << endl;
    return 0;
}