#include <bits/stdc++.h>

using namespace std;

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

int main() {

    int b[801], n, sol = 0;

    f>>n;

    for(int i = 0; i < n - 2; i++)
        for(int j = i + 1; j < n - 1; j++)
            for(int k = j + 1; j < n; k++)
                if(b[i] + b[j] > b[k] && b[i] + b[k] > b[j] && b[j] + b[k] > b[i]) sol++;
    cout<< sol;
}