#33110: JAVA
11146002@ntub.edu.tw
(吳沁學)
import java.util.Scanner;
public class a042 {
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
while(sc.hasNext()){
int i = sc.nextInt();
int n = (int) ((Math.pow(i, 2))-i+2);
System.out.println(n);
}
}
}