/* -*- coding: utf-8 -*-
 *
 * 1187.cc:  No.1187 皇帝ペンギン - yukicoder
 */

#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<cmath>
#include<iostream>
#include<string>
#include<vector>
#include<map>
#include<set>
#include<stack>
#include<list>
#include<queue>
#include<deque>
#include<algorithm>
#include<numeric>
#include<utility>
#include<complex>
#include<functional>
 
using namespace std;

/* constant */

const int MAX_N = 1000;

/* typedef */

/* global variables */

/* subroutines */

bool check(int x) {
  printf("? %d\n", x); fflush(stdout);

  char s[8];
  scanf("%s", s);
  return (s[0] == 's');
}

/* main */

int main() {
  int x0 = 0, x1 = MAX_N;
  while (x0 + 1 < x1) {
    int x = (x0 + x1) / 2;

    if (check(x)) x0 = x;
    else if (check(x + 1)) x0 = x + 1;
    else x1 = x;
  }

  printf("! %d\n", x1 - 1);
  fflush(stdout);
  return 0;
}