import java.util.*;

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

        while(true){

            String x = sc.next();
            int ans=0;

            if(x.equals("0")){break;}
            else{
                for(int i=0;i<x.length();i++){
                    ans += (x.charAt(i)-'0');
                }
                System.out.println(ans);
                ans = 0;
            }
        }
    }
}

/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