#include <bits/stdc++.h>
using namespace std;
#define rep(i,n) for(int i = 0; i < (int)n; i++)
using ll = long long;

int main(){
  int l = 0, r = 1000;
  string s;
  while(r-l > 1) {
    int m = (l + r) / 2;
    cout << "? " << m << endl;
    fflush(stdout);
    cin >> s;
    if(s == "safe") l = m;
    else {
      cout << "? " << m+1 << endl;
      fflush(stdout);
      cin >> s;
      if(s == "safe") l = m+1;
      else r = m;
    }
  }
  cout << "! " << l << endl;
  return 0;
}