#include <bits/stdc++.h>
using namespace std;
int v[1025];
unordered_map <int,int> harta[1025];
int main()
{
    freopen("oite.in","r",stdin);
    freopen("oite.out","w",stdout);
    int n,l,i,j;
    cin>>n>>l;
    for(i=1;i<=n;i++)
        cin>>v[i];
    for(i=n-1;i>=1;i--)
    {
        harta[i]=harta[i+1];
        for(j=i+1;j<=n;j++)
            harta[i][v[i]+v[j]]++;
    }
    long long rez=0;
    for(i=1;i<=n-3;i++)//prima oaie
        for(j=i+1;j<=n-2;j++)//a doua oaie
            rez+=harta[j+1][l-v[i]-v[j]];
    cout<<rez;
    return 0;
}