import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
public class Main {
	public static void main(String[] args)throws IOException {
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));

		String dat;
		dat=br.readLine();
		
		do{
			int i=0;
			int g=0;
			do{
				g += Integer.parseInt(dat.substring(i,i+1));
				i++;
			} while(i<dat.length());
			System.out.println(g);
			dat=br.readLine();
		}while(dat.equals("0")==false);
		
	}

}
/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