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

using namespace std;

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

const int NMAX = 2000;

int n, s, res;
int a[1 + NMAX];

unordered_map < int, short > sums;

int main()
{
  in >> n >> s;
  for(int i = 1 ; i <= n; i++)
    in >> a[i];
  sort(a + 1, a + n + 1);

  for(int i = 1; i <= n; i++) {
    for(int j = i + 1; j <= n; j++)
      res += sums[s - a[i] - a[j]];
    for(int j = 1; j < i; j++)
      sums[a[i] + a[j]]++;
  }

  out << res;
  in.close();
  out.close();
}