#include <bits/stdc++.h>
using namespace std;
int main(){
  int N, M;
  cin >> N >> M;
  vector<int> A(N);
  for (int i = 0; i < N; i++){
    cin >> A[i];
  }
  if (M % 2 == 1){
    cout << 0 << endl;
  } else {
    set<int> st;
    sort(A.begin(), A.end());
    long long ans = 0;
    for (int i = 0; i < N; i++){
      if (A[i] <= M / 2){
        if (binary_search(A.begin(), A.end(), A[i] + M / 2)){
          ans += N - 2;
        }
      }
    }
    cout << ans << endl;
  }
}