#include <bits/stdc++.h>
using namespace std;
#define FOR(i,a,b) for(int i=(a);i<(b);++i)
#define REP(i,n) FOR(i,0,n)
#define ALL(v) begin(v),end(v)
template<typename A, typename B> inline bool chmax(A & a, const B & b) { if (a < b) { a = b; return true; } return false; }
template<typename A, typename B> inline bool chmin(A & a, const B & b) { if (a > b) { a = b; return true; } return false; }
using ll = long long;
using pii = pair<int, int>;
constexpr ll INF = 1ll<<30;
constexpr ll longINF = 1ll<<60;
constexpr ll MOD = 1000000007;
constexpr bool debug = false;
//---------------------------------//

int main() {
	auto query = [](int q) -> bool {
		if (q < 0) return true;
		cout << "? " << q << endl;
		string res;
		cin >> res;
		return res == "out";
	};
	
	int ans = 0;
	int l = -1, r = 1000;
	while (r - l > 1) {
		int m = (l + r) >> 1;
		
		bool a = query(m - 1);
		bool b = query(m);
		if (!a) chmax(ans, m - 1);
		if (!b) chmax(ans, m);
		if (a & b) r = m;
		else l = m;
	}
	if (!query(r)) chmax(ans, r);
	
	printf("! %d\n", ans);
}