#include <bits/stdc++.h>
#define Nmax 1030

using namespace std;

unordered_map <int,int> M;
int n,S,a[Nmax];
long long sol;

int main()
{
    int i,j;
    ifstream cin("oite.in");
    ofstream cout("oite.out");
    cin>>n>>S;
    for(i=1;i<=n;++i) cin>>a[i];
    sort(a+1,a+n+1);
    for(i=1;i<=n && a[i]<=S;++i)
    {
        for(j=i+1;j<=n && a[i]+a[j]<=S;++j) sol+=M[S-a[i]-a[j]];
        for(j=i-1;j;--j) ++M[a[i]+a[j]];
    }
    cout<<sol;
    return 0;
}