#include <bits/stdc++.h>

using namespace std;

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

const int DIM = 1030;

unordered_map <int, int> H;

int v[DIM];

int n, m;
long long ans;

int i, j;

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

	for(i = 2; i < n; i++)
	{
		for(j = i + 1; j <= n; j++)
			ans += H[m - (v[i] + v[j])];
		
		for(j = 1; j < i; j++)
			H[v[i] + v[j]]++;
	}
	
	out << ans;
}