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

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

int v[1025];
unordered_map <int,int> harta;

int main()
{
    int n, l, i, j;
    long long rez = 0;
    in >> n >> l;
    for(i = 1; i <= n; i++)
        in >> v[i];
    for(i = 1; i <= n; i++)
    {
        for(j = i + 1; j <= n; j++)
            if(harta.find(l - v[i] - v[j]) != harta.end())
                rez += harta[l - v[i] - v[j]];
        for(j = 1; j < i; j++)
            harta[v[i] + v[j]]++;
    }
    out << rez;
    return 0;
}