#include <iostream>
#include <iomanip>
#include <cstdio>
#include <queue>
#include <cstring>
#include <vector>
#include <map>
#include <algorithm>
#include <cctype>
#include <cmath>
#include <bitset>
#include <set>
#include <stack>
using namespace std;

#define REP(i,n) for(int i=0;i<(int)(n);i++)
#define RREP(i,n) for(int i=n-1;i>=0;i--)
#define FOR(i,k,n) for(int i=(k);i<(int)(n);i++)
#define all(i,n) (i),(i+n)

int dx4[4]={1,0,-1,0};
int dy4[4]={0,-1,0,1};
int dx8[8]={1,0,-1,1,-1,1,0,-1};
int dy8[8]={1,1,1,0,0,-1,-1,-1};
int dx9[9]={0,1,0,-1,1,-1,1,0,-1};
int dy9[9]={0,1,1,1,0,0,-1,-1,-1};

typedef pair<int, int> P;
typedef pair<string, int> SP;
typedef long long ll;
typedef pair<ll, ll> PLL;

const int INF = 1e9;
const ll LLINF = 1e18;
const int MAX_V = 1e6+1;
const ll mod = 1000000007;
// << fixed << setprecision
// --------------------------------------
bool check(int n) {
  cout << "? " << n << endl << flush;
  string s;
  cin >> s;
  return (s == "safe");
}

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

  int l = 0, r = 1001;
  while(r - 1 > l) {
    int mid = (l + r) / 2;
    if(check(mid)) {
      l = mid;
    } else if(check(mid + 1)) {
      l = mid + 1;
    } else {
      r = mid;
    }
  }

  cout << "! " << r - 1 << endl << flush;
}