#include <bits/stdc++.h>

using namespace std;

ifstream f("oite.in");
ofstream g("oite.out");

int v[1025];
unordered_map<long long,long long>m;

int main()
{
    int n,s,i,j,x;
    long long sum=0;
    f>>n>>s;
    for(i=1;i<=n;i++)
        f>>v[i];

    for(i=1;i<=n;i++)
    {
        for(j=i+1;j<=n;j++)
        {
            sum+=m[s-(v[i]+v[j])];
            //cout<<m[s-(v[i]+v[j])]<<" ";
        }
        if(i>=2)
            for(j=1;j<i;j++)
                m[v[i]+v[j]]++;
    }
    g<<sum;
}