#include <string>
#include <iostream>
using namespace std;
string ask(int x) {
	cout << "? " << x << endl;
	string str;
	cin >> str;
	return str;
}
int main() {
	int l = 0, r = 1024;
	while (r - l > 1) {
		int m = (l + r) >> 1;
		if (ask(m) == "out" && ask(m + 1) == "out") {
			r = m;
		}
		else {
			l = m;
		}
	}
	cout << "! " << r - 1 << endl;
	return 0;
}