package text.java;

import java.util.Scanner;

public  class c{
    public static void main(String[]args) {
        double a = 0;
        int n;
        Scanner b=new Scanner(System.in);
        n=b.nextInt();
        for (int i = 1; i <= n; i++) {
            a =a+i*i;
        }
        System.out.println(a);


        }

    }