#include <iostream>
#include <fstream>
#include <algorithm>
#define N 802
using namespace std;
ifstream in("nrtri.in");
ofstream out("nrtri.out");
long long sol;
int n, a[N];

bool is_triangle(int x, int y, int z) {
        if (x + y >= z && y + z >= x && x + z >= y)
                return true;
        return false;
}

int main() {
        in >> n;
        for (int i = 1; i <= n; i++)
                in >> 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 && is_triangle(a[i], a[j], a[k]); k++)
                                sol++;
                }
        }

        out << sol;
        return 0;
}