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

int n, l, a[1030];
long long ans = 0;
unordered_map<int, int> mp;

int main()
{
    f >> n >> l;
    for (int i=1; i<=n; ++i)
        f >> a[i];

    for (int i=1; i<=n; ++i) {
        for (int j=i+1; j<=n; ++j)
            if (mp.find(l - a[i] - a[j]) != mp.end())
                ans += mp[l - a[i] - a[j]];
        for (int j=1; j<=i-1; ++j)
            mp [a[j] + a[i]]++;
    }

    g << ans;
    return 0;
}