#include <bits/stdc++.h>
#define fi first
#define se second
#define rep(i,s,n) for (int i = (s); i < (n); ++i)
#define rrep(i,n,g) for (int i = (n)-1; i >= (g); --i)
#define all(a) a.begin(),a.end()
#define rall(a) a.rbegin(),a.rend()
#define len(x) (int)(x).size()
#define dup(x,y) (((x)+(y)-1)/(y))
#define pb push_back
#define eb emplace_back
#define Field(T) vector<vector<T>>
using namespace std;
using ll = long long;
using ull = unsigned long long;
template<typename T> using pq = priority_queue<T,vector<T>,greater<T>>;
using P = pair<int,int>;
template<class T>bool chmax(T&a,T b){if(a<b){a=b;return 1;}return 0;}
template<class T>bool chmin(T&a,T b){if(b<a){a=b;return 1;}return 0;}

int main() {
  // int a = 1000000;
  // int p, q = -1;
  function<int(int)> output = [&](int x) {
    cout << "? " << x << endl;
    // p = q;
    // q = x;
    // return abs(a-p) >= abs(a-q);
    int ret;
    cin >> ret;
    return ret;
  };
  int l = 1, r = 1000001;
  int x = -1, y = -1;
  cout << "? " << x << endl;
  int cnt = 0;
  while(r-l > 1) {
    int mid = (r+l)/2;
    cout << l << " " << r << endl;
    if (cnt % 2 == 0) {
      y = 2*mid-x;
      int b = output(y);
      if (b) l = mid;
      else r = mid;
    } else {
      x = 2*mid-y;
      int b = output(x);
      if (b) r = mid+1;
      else l = mid+1;
    }
    ++cnt;
  }
  cout << "! " << l << endl;
  return 0;
}