import java.io.*;

class Main {
    public static void main(String[] arg)throws IOException{
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        while(true){
            String str = br.readLine();
            if(str.equals("0"))break;
            int sum = 0;
            for(int i=0;i<str.length();i++){
                sum = sum + Integer.parseInt("" +str.charAt(i));
            }
            System.out.println(sum);
        }
    }
}
/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