#include <tr1/unordered_map>

#include <fstream>

using namespace std;

using namespace tr1;

string z="oite.";

ifstream f(z+"in");

ofstream g(z+"out");



int C,L,i,j,rasp,v[1050];

unordered_map<int,int> m;



int main()

{

    f>>C>>L;

    for (i=1;i<=C;++i)

        f>>v[i];

    for(i=1;i<=C;++i)

    {

        for(j=i+1;j<=C;++j)

            rasp+=m[L-v[i]-v[j]];

        for(j=i-1;j;--j)

            ++m[v[i]+v[j]];

    }

    g<<rasp;



return 0;

}