import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.*;
import java.util.*;
public class Main {
    public static void main(String[] args) throws Exception {
        // Here your code !
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        long sum = 0;
        while(true) {
            sum = 0;
            String line = br.readLine();
            if(line.length()==1)
                if(Integer.parseInt(line)==0)break;
            for(int i=0;i<line.length();i++){
                sum += Integer.parseInt(String.valueOf(line.charAt(i)));
            }
            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