public class Main {
	public static void main(String[] args){
		java.util.Scanner scan = new java.util.Scanner(System.in);
		while(true){
			String x = scan.nextLine();
			if("0".equals(x)){
				break;
			}
			int sum = 0;
			for(char v : x.toCharArray()){
				sum += Integer.parseInt(String.valueOf(v));
			}
			System.out.println(sum);
		}
	}

}
/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