#include <bits/stdc++.h>

using namespace std;

#define REP(i,n) for(int i=0; i<(int)(n); i++)
#define FOR(i,b,e) for (int i=(int)(b); i<(int)(e); i++)
#define ALL(x) (x).begin(), (x).end()

const double PI = acos(-1);

bool check(int x) {
  cout << "? " << x << endl;
  cout.flush();
  string r;
  cin >> r;
  return r == "safe";
}

int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);

  int lo = 0, hi = 1000;
  while (hi - lo > 1) {
    int mi = (lo + hi) / 2;
    if (check(mi))
      lo = mi;
    else if (check(mi+1))
      lo = mi + 1;
    else
      hi = mi;
  }
  cout << "! " << lo << endl;
  
  return 0;
}