#include "bits/stdc++.h"
using namespace std;

// コンテスト中のみ
//#define int long long

#define ll long long
#define rep(i,n) for(int i = 0; i < (n); i++)
#define P pair<ll,ll>
#define ld long double
ll INF = (1LL << 60);
int MOD = 998244353;

signed main() {
	ios::sync_with_stdio(false);
	cin.tie(nullptr);
	ll l = -1, r = 1010;
	while (r - l > 1) {
		ll mid = (l + r) / 2;
		cout << "?" << " " << mid << endl;
		fflush(stdout);
		string s; cin >> s;
		if (s == "safe") {
			l = mid;
		}
		else {
			cout << "? " << mid + 1 << endl;
			fflush(stdout);
			string s; cin >> s;
			if (s == "safe")l = mid + 1;
			else r = mid;
		}
	}
	cout << "!" <<" "<<l << endl;
	return 0;
}