import java.util.ArrayList;
import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		// TODO ?????????????????????????????????????????????
		Scanner sc = new Scanner(System.in);

		ArrayList<String> lines = new ArrayList<String>();
		int c = 0;

		while (true) {
			String next = sc.nextLine();

			if (next.equals("0")) {
				break;
			}
			lines.add(next);
			c++;
		}

		for (int i = 0; i < c; i++) {
			String s = lines.get(i);
			int sum = 0;
			for (int j = 0; j < s.length(); j++) {
				int in = Integer.parseInt(s.substring(j, j + 1));
				sum += in;
			}
			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