import java.io.*;
import java.util.*;
import java.text.*;
import java.math.*;
import java.util.regex.*;

public class Solution {

    static long sumOfGroup(int k) {
        // Return the sum of the elements of the k'th group.
        long median=k*k;
        long sum=0;
        if(median%2==0){
            for(int i=0;i<k/2;i++){
                sum+=(median-1)-(i*2);
                sum+=(median-1)+(i*2);
            }
        }else{
            sum=median;
            for(int i=0;i<(k-1)/2;i++){
                sum+=median-(i*2);
                sum+=median+(i*2);
            }
        }
        return sum;
    }

    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        int k = in.nextInt();
        long answer = sumOfGroup(k);
        System.out.println(answer);
        in.close();
    }
}