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

class Main {

	public static void main(String[] args) throws IOException {

		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));

		String str = br.readLine();

		int sum = 0;

		while (!(str.equals("0"))) {

			sum =0;

			for (int i = 0; i < str.length(); i++) {
				sum += Integer.parseInt(String.valueOf(str.charAt(i)));
			}
			System.out.println(sum);

			str = br.readLine();
		}

	}
}
/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