#include <bits/extc++.h>

#ifndef DUMP
#define DUMP(...) (void)0
#endif

using namespace std;

int main() {
  cin.tie(nullptr)->sync_with_stdio(false);
  auto f = [](int x) {
    cout << "? " << x << endl;
    string s;
    cin >> s;
    return s[0] == 's';
  };
  if (not f(1)) {
    cout << "! 0" << endl;
    exit(0);
  }
  int ok = 0, ng = 1000;
  while (ng - ok > 1) {
    int mid = (ok + ng) / 2;
    (f(mid) or f(mid + 1) ? ok : ng) = mid;
  }
  int res = ok + f(ok + 1);
  cout << "! " << res << endl;
}