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

public class Main {
	public static void main(String[] args) {
		BufferedReader buf = new BufferedReader(new InputStreamReader(System.in));
		StringBuilder output = new StringBuilder();
		String line;
		int c;
		int sum = 0;
		try {
			while((line = buf.readLine()) != null) {
				for (int i = 0; i < line.length(); i++) {
					c = Integer.parseInt("" + line.charAt(i));
					sum += c;
				}
				if (sum == 0) break;
				output.append(sum).append('\n');
				sum = 0;
			}
			System.out.print(output);
		} catch (IOException e) {
			e.printStackTrace();
		}
	}

}
/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