#include<stdio.h>
long nr[1000001],i,j,d,c,l,x[2025],n;
long long NR;
int main()
{
	freopen ("oite.in","rt",stdin);
	freopen ("oite.out","wt",stdout);

	scanf("%ld %ld",&n,&l);

	for (i=1;i<=n;i++)
		scanf("%ld",&x[i]);

	for (c=1;c<=n;c++)
	{
		for (d=c+1;d<=n;d++)
		{
			NR+=nr[l-x[c]-x[d]];
		}
		for (d=1;d<=c-1;d++)
			nr[x[d]+x[c]]++;
	}
	printf("%lld\n",NR);
	return 0;
}