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

public class Main{
	public static void main(String[] args) throws IOException {
		BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
		short size, sum;
		while (true) {
			sum = 0;
			String input = in.readLine();
			if (input.equals("0")) {
				break;
			}
			size = (short) input.length();
			char[] charNum = input.toCharArray();
			for (int i = 0; i < size; i += 1) {
				charNum[i] = input.charAt(i);
				sum += Short.parseShort(Character.toString(charNum[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