#include <bits/stdc++.h>
using namespace std;

typedef long long ll;
#define REP(i,n) for(int i=0,_n=(int)(n);i<_n;++i)
#define ALL(v) (v).begin(),(v).end()
#define CLR(t,v) memset(t,(v),sizeof(t))
template<class T1,class T2>ostream& operator<<(ostream& os,const pair<T1,T2>&a){return os<<"("<<a.first<<","<<a.second<< ")";}
template<class T>void pv(T a,T b){for(T i=a;i!=b;++i)cout<<(*i)<<" ";cout<<endl;}
template<class T>void chmin(T&a,const T&b){if(a>b)a=b;}
template<class T>void chmax(T&a,const T&b){if(a<b)a=b;}

ll nextLong() { ll x; scanf("%lld", &x); return x;}


int memo[1005];

int query(int x) {

  if (x <= 0) return 1;
  if (memo[x] != -1) return memo[x];

  cout << "? " << x << endl;

  int res = 0;

  string s;
  cin >> s;
  res = (s == "safe");

  // int N = 1000;
  // int D = 10;
  // if (x >= N || x % D == 0)
  //   res = 0;
  // else
  //   res = 1;

  return memo[x] = res;
}

int main() {

  CLR(memo, -1);

  int hi = 1000;
  int lo = 0;

  while (hi - lo > 2) {
    int mi = (hi + lo) / 2;
    if (query(mi) == 0 && query(mi+1) == 0) {
      hi = mi;
    } else {
      lo = mi;
    }
  }

  int ans = hi;
  while (query(ans) == 0) ans--;
  cout << "! " << ans << endl;
  return 0;
}