import java.io.*;

public class Main {

	public static void main(String[] args)throws IOException
	{
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		String[] str = new String[1000];
		int sum = 0;
		while(true)
		{
			str = br.readLine().split("");
			for(int i=0; i<str.length; i++)
			{
				sum += Integer.parseInt(str[i]);
			}
			if(sum==0)	break;
			System.out.println(sum);
			sum = 0;
		}
	}
}
/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