#include <bits/stdc++.h>

using namespace std;
ifstream f("oite.in");
ofstream g("oite.out");
int n, ans, v[1100], l;
unordered_map<int, int> h;

int main()
{
    f >> n >> l;
    for (int i = 1; i <= n; ++i) f >> v[i];
    for (int i = 3; i < n; ++i) {
        for (int j = i - 2; j >= 1; --j) h[v[j] + v[i - 1]]++;
        for (int j = i + 1; j <= n; ++j) ans += h[l - v[j] - v[i]];
    }
    g << ans << '\n';
    return 0;
}