#include <bits/stdc++.h>
using namespace std;

#define fi first
#define se second
int n, l, a[1030], ans;
unordered_map <int, int> M; //perechi de cate 2

int main(){
    ifstream cin ("oite.in");
    ofstream cout ("oite.out");
    cin >> n >> l;
    for (int i=1; i<=n; i++) cin >> a[i];
    for (int i=3; i<n; i++){
        for (int j=1; j < i-1; j++) M[a[i-1]+a[j]]++;
        for (int j=i+1; j<=n; j++) ans += M[l - a[i] - a[j]];
    }
    cout << ans;
    return 0;
}