import java.io.*;
import java.util.*;

public class Main{
	public static void main(String args[]) throws IOException{
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		ArrayList<Integer> ans = new ArrayList<Integer>();
		char ch[] = new char[1000];
		int len, sum;
		String str;
		
		while(true){
			str = br.readLine();
			if(str.equals("0")){
				break;
			}
			
			sum = 0;
			len = str.length();
			ch = str.toCharArray();
			
			for(char c : ch){
				sum += Character.digit(c, 10);
			}
			
			ans.add(sum);
		}
		
		for(int i : ans){
			System.out.println(i);
		}
	}
}
/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