#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;
}