#include <algorithm>
#include <fstream>
#include <unordered_map>
using namespace std;
ifstream in("oite.in");
ofstream out("oite.out");
long long a[1050], rs;
unordered_map <long long, int> m;
int main()
{
    int n, S;
    in >> n >> S;
    for(int i = 0; i < n; i++)
        in >> a[i];
    sort(a, a + n);
    for(int i = 0; i < n; i++)
    {
        for(int j = i + 1; j < n; j++)
            rs += m[S - a[i] - a[j]];
        for(int j = 0; j < i; j++)
            m[a[i] + a[j]]++;
    }
    out << rs;
    return 0;
}