#include <fstream>
#include <unordered_map>
#include <algorithm>
using namespace std;
unordered_map <int,int> m;
const int i,j,l,n,a,sol,
int v[1026];
int main()
{
    ifstream f ("oite.in");
    ofstream g ("oite.out");
    f>>n>>l;
    for (i=1;i<=n;i++)
            f>>v[i];
    sort(v+1,v+n+1);
    for (i=1;i<=n;i++)
        {
          for (j=i+1;j<=n;j++) sol+=m[l-v[i]-v[j]];
          for (j=1;j<i;j++) m[v[i]+v[j]]++;
        }
    g<<sol;
}