#include <fstream>
#include <unordered_map>
#define VAL 1035

using namespace std;

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

int N, SUM, i, j;
int v[VAL], ans, s;
unordered_map<int, int> h;

int main()
{
    fin >> N >> SUM;
    for (i=1; i<=N; i++)
      fin >> v[i];
    for (i=1; i<=N; i++)
    {
        for (j=i+1; j<=N; j++)
        {
            s=v[i]+v[j];
            if (s<SUM)
              ans+=h[SUM-s];
            else
              break;
        }
        for (j=1; j<i; j++)
          h[v[i]+v[j]]++;
    }
    fout << ans << '\n';
    fin.close();
    fout.close();
    return 0;
}