import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

class Main{
	public static void main(String[] args) throws IOException{
    	BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
    	String input;
    	int total = 0;

    	while((input = br.readLine()) != null){
    		if(input.equals("0")) break;
    		char[] cArray = input.toCharArray();
    		for(char c : cArray){
    			total += Character.getNumericValue(c);
    		}
    		System.out.println(total);
    		total = 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