import java.util.Scanner;

public class Main {

	public static void main(String[] args) {

		// ?????????????????\??????????????§??????
		Scanner sc = new Scanner(System.in);

		while (true) {

			// ?????????????????\???
			String input = sc.nextLine();

			// 0?????\?????????????????????
			if (input.equals("0"))
				break;

			// ??\?????????????????????char????????????
			char[] sentence = input.toCharArray();

			// ????¨?????????\???????????°
			int sum = 0;

			// ???????????°??????????¨?????¨????????????????
			for (int cnt = 0; cnt < sentence.length; cnt++) {

				sum += Character.getNumericValue(sentence[cnt]);

			}
			System.out.println(sum);
		}
		sc.close();
	}
}
/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