import java.util.Scanner;

public class No276 {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();
		
		if(N % 2 == 1) {
			System.out.println(N);
		}else {
			System.out.println(N/2);
		}
	}
}