#include <fstream>
#include <algorithm>
using namespace std;

ifstream fin ("nrtri.in");
ofstream fout ("nrtri.out");

int cautare(int l, int r);

int v[10000];
int n;

int main()
{

    fin >> n;
     for (int i = 1; i <= n; i++)
            fin >> v[i];
     sort(v + 1, v + 1 + 1);

        fout << cautare(1, n);

}

int cautare(int l, int r)
{
    int m;
    for (int i = 0; i < n - 2; i++)
        for (int j = 0; j < n - 1; j++)
        {
            m = (l + r) / 2;
  while (l <= r)
    {
      if ((v[m] <= v[i] + v[j] && v[m + 1] > v[i] + v[j]) || (v[m] <= v[i] + v[j] && m == n - 1))
    return m;
   else
    if (v[m] <= v[i] + v[j] && v[m + 1] <= v[i] + v[j])
        {
              l = m + 1;
              m = (l + r) / 2;
        }
           else
       {
            r = m - 1;
            m = (l + r) / 2;
       }
  }
        return 0;
        }


}