#include <bits/stdc++.h>
std::ifstream cin("oite.in");
std::ofstream cout("oite.out");
int n,s,ans,v[1025];
std::unordered_map<int,int>a;
int main()
{
    cin>>n>>s;
    for(int i=1;i<=n;++i)
        cin>>v[i];
    std::sort(v+1,v+n+1);
    for(int i=1;i<=n;++i)
    {
        for(int j=i+1;j<=n;++j)
        {
            if(v[i]+v[j]>s)
                break;
            ans+=a[s-(v[i]+v[j])];
        }
        for(int j=i-1;j>=1;--j)
            ++a[v[i]+v[j]];
    }
    cout<<ans;
    return 0;
}