#include <fstream>
#include <unordered_map>
#include <algorithm>

using namespace std;

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

#define int long long

const int max_size = 1025;

int a[max_size];
unordered_map <int, int> m;

signed main ()
{
    int n, k, ans = 0;
    in >> n >> k;
    for (int i = 1; i <= n; i++)
    {
        in >> a[i];
    }
    sort(&a[1], &a[n + 1]);
    for (int i = 1; i < n; i++)
    {
        for (int j = i + 1; j <= n; j++)
        {
            /// ma uit in spate ce perechi am
            if (a[i] + a[j] > k)
            {
                break;
            }
            ans += m[k - a[i] - a[j]];
        }
        for (int j = 1; j < i; j++)
        { /// bag perechiile noi
            m[a[i] + a[j]]++;
        }
    }
    out << ans;
    in.close();
    out.close();
    return 0;
}