import java.io.BufferedReader;
import java.io.InputStreamReader;

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

			}catch (Exception e) {
				System.err.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