import java.util.*;
public class Main {
	public static void main(String[] args) {
		Scanner scn = new Scanner(System.in);
		long n = scn.nextLong();
		long ans=0;
		long i=1;
		while(n>0) {
			n/=2;
			ans+=i;
			i*=2;
		}System.out.println(ans);
	}
}
/tmp/hf-datasets-cache/medium/datasets/42704881117311-config-parquet-and-info-qiankunmu-Project_CodeNet-896c9d36/hub/datasets--qiankunmu--Project_CodeNet_Python800_and_Java250/snapshots/c899fde44a77ba1cc14973ed3de064e4ff3aadc7/Project_CodeNet_Java250.tar.gz