import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);

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

			if (str.equals("0"))
				break;
			char[] sen = str.toCharArray();
			int sum = 0;

			for (int i = 0; i<sen.length; i++) {
				sum += Character.getNumericValue(sen[i]);
			}
			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