#include "bits/stdc++.h"
using namespace std;
#define int long long
#define REP(i, n) for (int i = 0; i < (int)n; ++i)
#define RREP(i, n) for (int i = (int)n - 1; i >= 0; --i)
#define FOR(i, s, n) for (int i = s; i < (int)n; ++i)
#define RFOR(i, s, n) for (int i = (int)n - 1; i >= s; --i)
#define ALL(a) a.begin(), a.end()
#define IN(a, x, b) (a <= x && x < b)
template<class T>istream&operator >>(istream&is,vector<T>&vec){for(T&x:vec)is>>x;return is;}
template<class T>inline void out(T t){cout << t << "\n";}
template<class T,class... Ts>inline void out(T t,Ts... ts){cout << t << " ";out(ts...);}
template<class T>inline bool CHMIN(T&a,T b){if(a > b){a = b;return true;}return false;}
template<class T>inline bool CHMAX(T&a,T b){if(a < b){a = b;return true;}return false;}
constexpr int INF = 1e18;



signed main(){
	auto f =[&](int x){
		int flg = 0;//隣り合う2数がアウトならxはN以上
		cout << '?' << " " << x << endl;
		string s;
		cin >> s;
		if(s == "safe") flg = 1;
		cout << '?' << " " << x + 1 << endl;
		cin >> s;
		if(s == "safe") flg = 1;
		return flg;
	};
	int l = -1, r = 1000 + 2;
	REP(_, 10){
		int c = (l + r) / 2;
		if(f(c)) l = c;
		else r = c;
	}
	RFOR(i, 1, l + 2) {
		cout << "?" << " " << i << endl;
		string s;
		cin >> s;
		if(s == "safe") {
			cout << "!" << " " << i << endl;
			return 0;
		}
	}
}