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

public class Solution {

    static long sumOfGroup(long k) {
                if(k == 1){
            return 1;
        }
        if(k % 2 == 0){
            long square = (long)Math.pow(k,2);
            long count = k/2;
            long sum = 0;
            square--;
            for(; count > 0; count--){
                sum += square;
                square = square - 2;
            }
            count = k/2;
            square = (long)Math.pow(k,2);
            square++;
            for(; count > 0; count--){
                sum += square;
                square += 2;
            }
            return sum;
        }else{
             long square = (long)Math.pow(k,2);
            long count = k/2;
            long sum = square;
            square -= 2;
            for(; count > 0; count--){
                sum += square;
                square = square - 2;
            }
            count = k/2;
            square = (long)Math.pow(k,2);
            square += 2;
            for(; count > 0; count--){
                sum += square;
                square += 2;
            }
            return sum;
        }
        // Return the sum of the elements of the k'th group.
    }

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