//50 tle
#include <stdio.h>
#include <map>
using namespace std;
#define nmax 1030
long n, s, i, v[nmax], j, rez, poz, a, b;
map <int, int> ma1;
map <int, int> :: iterator it;

void citire()
{
	scanf("%ld %ld",&n,&s);
	for (i=1;i<=n;i++)
		scanf("%ld",&v[i]);
}

void rezolvare()
{
	ma1[v[1]+v[2]]++;
	for (poz=3;poz<=n-1;poz++)
	{
		for (i=poz+1;i<=n;i++)
			rez+=ma1[s-v[poz]-v[i]];
		for (i=1;i<=poz-1;i++)
			ma1[v[i]+v[poz]]++;
	}
	printf("%ld",rez);
}

int main()
{
	freopen("oite.in","r",stdin);
	freopen("oite.out","w",stdout);
	citire();
	rezolvare();
	return 0;
}