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

int main()
{
	ifstream fin("ntri.in");
	ofstream fout("ntri.out");
	int n, v[100], l = 0;
	fin >> n;
	for (int i = 1; i <= n; i++)
		fin >> v[i];
	for (int i = 1; i <= n; i++)
		for (int j = i + 1; j <= n; j++)
			for (int k = j + 1; k <= n; k++)
				if (v[i] + v[j] > v[k] && v[j] + v[k] > v[i] && v[k] + v[i] > v[j])
					l++;
	fout << l;
}