#include <bits/stdc++.h>
using namespace std;
ifstream fin("oite.in");
ofstream fout("oite.out");
unordered_map<int,int>fr;
int v[1030],n,s,i,j,ans;
signed main()
{
    fin>>n>>s;
    for(i=1;i<=n;i++)
        fin>>v[i];
    sort(v+1,v+n+1);
    for(i=1;i<=n;i++)
    {
        for(j=i+1;j<=n;j++)
        {
            if(v[i]+v[j]>s)
                break;
            ans+=fr[s-v[i]-v[j]];
        }
        for(j=1;j<i;j++)
            fr[v[i]+v[j]]++;
    }
    fout<<ans;
    return 0;
}