#include <bits/stdc++.h>

using namespace std;
ifstream in("oite.in");
ofstream out("oite.out");
unordered_map<int,int> ap;
int v[1<<10+5];
int main()
{
    ios::sync_with_stdio(0);
    in.tie(0);
    int n,s,ans=0;
    in >> n >> s;
    for (int i = 0; i<n; i++)
        in >> v[i];
    sort(v,v+n);
    for (int i = 0; i<n; i++)
    {
        for (int j = i+1; j<n; j++)
            if (v[i]+v[j]<=s)
                ans+=ap[s-v[i]-v[j]];
            else
                break;
        for (int j = 0; j<i; j++)
            if (v[i]+v[j]<=s)
                ap[v[i]+v[j]]++;
            else
                break;
    }
    out << ans;
}