#include <fstream>
#include <unordered_map>
#include <algorithm>

using namespace std;
ifstream in("oite.in");
ofstream out("oite.out");
unordered_map<int, int> m;
int v[1025];
int main()
{
    int ans=0;
    int n,l,i,j;
    in>>n>>l;
    for (i=1; i<=n; i++)
    {
        in>>v[i];
    }
    sort(v+1,v+n+1);
    for (i=1; i<n; i++)
    {
        for (j=i+1; j<=n; j++)
        {
            int s=v[i]+v[j];
            if (m[l-s]>0)
                ans+=m[l-s];
        }
        for (j=i-1; j>=1; j--)
        {
            m[v[i]+v[j]]++;
        }
    }
    out<<ans;
    return 0;
}