#include <bits/stdc++.h>
#pragma GCC optimize("03")

using namespace std;

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

int n, L, a[2000];
unordered_map <int, int> pairs;
long long ans;

int main(){
	in >> n >> L;
	for(int i = 1; i <= n; i++)
		in >> a[i];
	for(int i = 3; i < n; i++){
		for(int p = 1; p < i - 1; p++)
			pairs[a[p] + a[i - 1]]++;
		for(int j = i + 1; j <= n; j++){
			if(L - a[i] - a[j] >= 0)
				ans += pairs[L - a[i] - a[j]];
		}
	}
	out << ans;
	return 0;
}