#!/bin/python3

import sys

def sumOfGroup(k):
    if(k%2==0):
        s=k*k
        s1=k*k
        s2=k*k
        sum1=2*s
        n=k/2-1
        s1=s1-1
        s2=s2+1
        while(n!=0):
            s1=s1-2
            s2=s2+2
            sum1=sum1+s1+s2
            n=n-1
    else:
        n=k//2
        s1=k*k
        s2=k*k
        sum1=k*k
        while(n!=0):
            s1=s1-2
            s2=s2+2
            sum1=sum1+s1+s2
            n=n-1
    return sum1
        
        

if __name__ == "__main__":
    k = int(input().strip())
    answer = sumOfGroup(k)
    print(answer)