# -*- coding: utf-8 -*-
char=int(input())
flag=char*2-1 # 2n - 1
l=1
s=0
k=char**2-flag
if char%2==0:
    for s in range(0,k,2):
        s+=l
elif char%2!=0:
    for s in range(1,k,2):
        s+=l
print('Квадрат числа равен: ', flag + s)