#include<fstream>
#include<unordered_map>
const std::string txt="oite";
std::ifstream cin(txt+".in");
std::ofstream cout(txt+".out");
#define int long long
int v[1025];
std::unordered_map <int,int> m;
signed main(int n,int sum,int nr){
    nr=0;
    cin>>n>>sum;
    for(int i=1;i<=n;++i)
        cin>>v[i];
    for(int i=1;i<=n;++i){
        int s;
        for(int j=i+1;j<=n;++j){
            s=v[i]+v[j];
            nr+=m[sum-s];
        }
        for(int j=1;j<i;++j){
            s=v[i]+v[j];
            ++m[s];
        }
    }
    cout<<nr;
}