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