!! Really Strange !!

import java.math.BigInteger;
import java.util.Scanner;

public class Main{
public static void main(String[] args )
{
Scanner cin = new Scanner(System.in);

while( cin.hasNext())
{
BigInteger n = cin.nextBigInteger();
if( n.equals(BigInteger.valueOf(0)))
{
System.out.println("1");
}
else
{
n = n.multiply(n).add(n.negate()).add(BigInteger.valueOf(2));
System.out.println(n);
}
}
}
}