#include <unordered_map>
#include <iostream>
#include <fstream>
using namespace std;
ifstream in("oite.in");
ofstream out("oite.out");
const int maxn = 1050;
unordered_map <int, int> mp;
int v[maxn];
int main()
{
    int n, L;
    in >> n >> L;
    for(int i = 1; i <= n; i++)
        in >> v[i];
    int sol = 0;
    for(int i = 1; i <= n; i++)
    {
        for(int j = i + 1; j <= n; j++)
        {
            int p = L - v[i] - v[j];
            if(p < 0)
                continue;
            sol += mp[p];
        }
        for(int j = 1; j < i; j++)
            mp[v[i] + v[j]]++;
    }
    out << sol << "\n";
    return 0;
}