#include <fstream>
#include <algorithm>
#include <unordered_map>

using namespace std;

ifstream cin ("oite.in");
ofstream cout ("oite.out");

const int NMAX = 1024;

int n, l;
long long sol;

int v[1 + NMAX];
unordered_map <int, int> f;

int main() {
  cin >> n >> l;
  for(int i = 1; i <= n; i++)
    cin >> v[i];
  sort(v + 1, v + n + 1);
  for(int i = 1; i <= n; i++) {
    for(int j = i + 1; j <= n; j++)
      sol += f[l - (v[i] + v[j])];
    for(int j = i - 1; j >= 1; j--)
      f[v[i] + v[j]]++;
  }
  cout << sol;
  return 0;
}