#include <iostream>
#include <unordered_map>
int v[1025];
std::unordered_map <int,int> harta;
int main()
{
    freopen("oite.in","r",stdin);
    freopen("oite.out","w",stdout);
    std::ios_base::sync_with_stdio(NULL);
    std::cin.tie(NULL);
    std::cout.tie(NULL);
    int n,l,i,j;
    long long rez=0;
    std::cin>>n>>l;
    for(i=1;i<=n;i++)
        std::cin>>v[i];
    for(i=2;i<=n-2;i++)
    {
        for(j=i-1;j>=1;j--)
            harta[v[i]+v[j]]++;
        for(j=i+2;j<=n;j++)
            rez+=harta[l-v[i+1]-v[j]];
    }
    std::cout<<rez;
    return 0;
}