import java.util.*;

public class Main {

	public static void main(String[] args) {
		int sum;
		String s;
		Scanner sc = new Scanner(System.in);
		while (true) {
			s = sc.next();
			sum = 0;
			if (s.equals("0"))
				break;
			for (int i = 0; i < s.length(); i++) {
				sum += Integer.parseInt(""+ s.charAt(i));
			}
			if (!s.equals("0"))
				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