#include <bits/stdc++.h>

using namespace std;
ifstream fin("oite.in");
ofstream fout("oite.out");
int n,l;
int v[1026];
int rez;
unordered_map<int,int> mapa;
int main()
{
    fin>>n>>l;
    for (int i=1;i<=n;i++) fin>>v[i];
    for (int i=1;i<=n;i++)
    {
        for (int j=i+1;j<=n;j++)
        {
            int sum=v[i]+v[j];
            if (mapa.find(l-sum)!=mapa.end()) rez=rez+mapa[l-sum];
        }
        for (int j=i-1;j>=1;j--)
            mapa[v[i]+v[j]]++;
    }
    fout<<rez;
    return 0;
}