#pragma GCC optimize ("-O2")
#include <tr1/unordered_map>

#include <fstream>
#define fast ios_base::sync_with_stdio(false);f.tie(0);g.tie(0)
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()

{
    fast;

    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;

}