import java.util.*;

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

		String s = sc.next();
      
		int s0 = Integer.parseInt(s.substring(0, 1));
		int s1 = Integer.parseInt(s.substring(1, 2));
		int s2 = Integer.parseInt(s.substring(2, 3));

		int s_t = s0 + s1 + s2;
		System.out.print(s_t);

	}
}
/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