import java.io.*;

public class Main{
    public static void main(String[] args){
        BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
        try{
            while(true){
                String line = reader.readLine();
                int sum = 0;
                if(line.charAt(0)=='0'){
                    break;
                }
                
                for(int i=0;i<line.length();i++){
                   String num = String.valueOf(line.charAt(i));
                   sum += Integer.parseInt(num);
                }
                System.out.printf("%d\n",sum);
            }
        }catch(IOException e){
            System.out.println(e);
        }
    }
}

/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