
import java.util.*;

class Main{
public static void main(String[] args){
Scanner sc = new Scanner(System.in);
for(;;){
int ans =0;
String s=sc.nextLine();
if(s.equals("0"))break;
for(int i=0; i<s.length(); i++){
	ans += Character.digit(s.charAt(i),10);
}
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