import java.io.*;

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