#include <bits/stdc++.h>
using namespace std;
ifstream fin("oite.in");
ofstream fout("oite.out");

int n, L, ans, v[1<<12];
unordered_map<int, int> ump;

int main()
{
    fin >> n >> L;

    for(int i = 1; i <= n; i ++)
        fin >> v[i];

    sort(v+1, v+n+1);

    for(int i = 1; i < n; ++i)
    {
        for(int j = i+1; j <= n; ++j)
        {
            if(L - v[i] - v[j] > 0)
                ans += ump[L - v[i] - v[j]];
        }
        for(int j = 1; j < i; ++j)
            ++ump[v[i] + v[j]];
    }

    fout << ans;

    return 0;
}