

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

public class Main {
	public static void main(String args[])throws IOException,NumberFormatException{
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		StringBuilder sb = new StringBuilder();
		String str;
		int sum;//????¨????????¨????????????¨
		char c;
		sum = 0;
		
		while(true){
			str=br.readLine();
			
			//String??????long????????????
			if(str.length() == 1){
				if(Integer.parseInt(str) == 0){
				break;
				}
			}
			//?????????????????????
			for(int count = 0;count<str.length();count++){
				//????????????????????????????????????????¶?????????????
				c = str.charAt(count);
				//Char??????String??????Long??????????????????????¨?????¶?????????????
				sum += Integer.parseInt(String.valueOf(c));
			}
		sb.append(sum);
		sb.append("\n");
		sum = 0;//?????????
		}
		
		//????????????????????????????????????("\n")?????¨???
		sb.deleteCharAt(sb.length()-1);
		System.out.println(new String(sb));
		
	}
}
/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