import java.io.*;

class Main{
    public static void main(String[]args)throws IOException{
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        
        String str;
        int sum = 0;

        while(true){
            str = br.readLine();

            if(str.equals("0"))break;
            
            for(int i=0; i<str.length(); i++){
                sum += Integer.parseInt(str.substring(i,i+1));
            }
            System.out.println(sum);
            sum = 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