#include <fstream>
#include <map>

using namespace std;

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

int n , l , ans;
int v[1500];

map <int , int> mp;

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

    for (int i = 1; i < n; ++i) {
        for (int j = i + 1; j <= n; ++j) {
            if (v[i] + v[j] <= l)
                ans += mp[l - v[i] - v[j]];
        }

        for (int j = 1; j < i; ++j) {
            ++mp[v[i] + v[j]];
        }
    }

    g << ans;
    return 0;
}