#include <fstream>
#include <unordered_map>
using namespace std;

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

#define NMAX 1030

int a[NMAX];
unordered_map<int, int> M;

int main() {
    int c, l;
    fin >> c >> l;
    for (int i = 1; i <= c; ++i) {
        fin >> a[i];
    }

    long long rez = 0;
    for (int i = 1; i <= c; ++i) {
        for (int j = i + 1; j <= c; ++j) {
            rez += M[l - a[i] - a[j]];
        }
        for (int j = 1; j < i; ++j) {
            M[a[i] + a[j]]++;
        }
    }

    fout << rez;
    return 0;
}