import java.util.*;

public class Main {
	public static void main(String[] args) throws Exception{
		Scanner scn = new Scanner(System.in);
		long n = scn.nextLong();
		long ans;
      	long count;
      	ans=count=0;
      	while(n != 0){
          n/=2;
          ans += Math.pow(2, count);
          count++;
        }
      	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