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

int n, k;

int mod(int i){return (i%n+n)%n;}

int q(int x){
 x = mod(x) + 1;
 cout << "? " << x << endl;
 int ret; cin >> ret;
 return ret;
}

int32_t main(){
 cin >> n >> k;
 int i=0, j=0, x;
 int lo, hi;
 while(1){
  x = q(j);
  if(x > k){lo = j-i-i, hi = j; break;}
  if(x < k){lo = j, hi = j+i+i; break;}
  j += i; ++i;
 }
 while(lo <= hi){
  int mid = (lo+hi)/2;
  int x = q(mid);
  if(x == k){
   cout << "! " << mod(mid) + 1 << endl;
   exit(0);
  }
  if(x < k) lo = mid+1;
  else hi = mid-1;
 }
}
