#include <bits/stdc++.h>

using namespace std;

int main () {
  int n, target;
  cin >> n >> target;
  vector <int> arr(n);
  for (int i = 0; i < n; i++) cin >> arr[i];

  map <int, vector <int>> pos;
  for (int i = 0; i < n; i++) {
    pos[arr[i]].push_back(i);
  }

  for (int x = 0; x < n; x++) {
    int k = target - arr[x];
    //a_y = k and y != x
    if (pos.count(k) == 1) {
      bool valid = false;
      int cnt = 0;
      for (int pos_y: pos[k]) {
        if (pos_y != x) {
          valid = true;
        }
        cnt++;
        if (cnt == 2) break;
      }

      if (valid) {
        // tienes tu respuesta
      }
    }
  }
  return (0);
}