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

ifstream f("nrtri.in");
ofstream g("nrtri.out");

int n, a[1000];
int cont;

int main()
{
    f>>n;
    for(int i = 1; i <= n; i++)
    {
        f>>a[i];
    }

    sort(a + 1, a + n + 1);
    for(int i = 1; i <= n - 2; i++)
        for(int j = i + 1; j <= n -1; j++)
            for(int k = j + 1; k <= n; k++)
                if(i != j && i != k && j != k)
                {
                    int maxx = a[k], minn = a[i];
                    int mid = a[j];
                    if(mid + minn >= maxx)
                    {
                        cont++;
                    }
                    else break;
                }

    g<<cont;
    return 0;
}