#include<bits/stdc++.h>
using namespace std;
unordered_map<int,short> sume;
int n,S, a[2000],rez;
int main()
{
	ifstream cin("oite.in");
	ofstream cout("oite.out");
	cin >> n >> S;
	for (int i = 0 ; i < n; i++)
		cin >> a[i];
	sort(a,a+n);
	for(int i = 0 ; i < n ; i++)
	{
		for (int j = i + 1; j < n; j++)
		{
			rez += sume[S - a[i] - a[j]];
		}
		for (int j = 0; j < i; j++) sume[a[i] + a[j]]++;
	}
	cout << rez;
}