import java.util.*;

class Main {
	public static void main(String[] args){
		final Scanner sc = new Scanner(System.in);
		StringBuilder sb = new StringBuilder();
		final String lb = System.getProperty("line.separator");
		while(true){
			char[] num = sc.nextLine().toCharArray();
			int sum = 0;
			if(num[0] == '0') break;
			for(int i = 0; i < num.length; i++){
				sum += Integer.parseInt(String.valueOf(num[i]));
			}
			sb.append(sum).append(lb);	
		}
		System.out.print(sb.toString());
	}
}
/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