#include <iostream>
#include <fstream>
#include <algorithm>

using namespace std;
ifstream fi("nrtri.in");
ofstream fo("nrtri.out");
int main()
{
    int pas, i, j, k=0, s=0, nr=0,v[1024],n;
    fi>>n;
    for(i=0;i<=n;i++)
    {
        fi>>v[i];
    }
    sort(v,v+n);
    pas=1<<10;
    for(i=0;i<=n-1;i++)
        for(j=i+1;j<=n;j++)
            {
                s=v[i]+v[j];
                while(pas!=0)
                    {
                        if((nr+pas<=n)&&(v[i+pas]<s)&&(v[i]+v[i+pas]>v[j])&&(v[j]+v[i+pas]>v[i]))
                            {
                                nr+=pas;
                            }
                        pas/=2;
                    }
            }
    fo<<nr-1;
    return 0;
}