#include <bits/stdc++.h>

using namespace std;
const int NMAX = 1030;

int N, L, M;
int v[NMAX];
long long ans;
unordered_map <int, int> hmap;

void read(){
    scanf("%d%lld", &N, &L);
    for(int i = 1; i <= N; i++)
        scanf("%d", &v[i]);
}

int main(){

    freopen("oite.in", "r", stdin);
    freopen("oite.out", "w", stdout);

    read();

    for(int i = 1; i <= N; i++){
        for(int j = i + 1; j <= N; j++)
            if(L - v[i] - v[j] > 0)
                ans += hmap[L - v[i] - v[j]];
        for(int j = 1; j < i; j++)
            hmap[v[i] + v[j]]++;
    }
    printf("%lld", ans);

    return 0;
}