#include <string>
#include <vector>
#include <algorithm>
#include <iostream>

using namespace std;

int comb(int ball, int bar){
    int temp = 1;
    for (int i = ball + bar; i > ball; --i){
        temp *= i;
    }
    
    int d = 1;
    for (int i = bar; i > 0; --i){
        d *= i;
    }
    return temp / d;
}

int main(){
    int input;
    while (cin >> input){
        cout << comb(input, 3) << endl; 
    }
    
}