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 str[];
        StringBuilder sb = new StringBuilder();
        int result;
        while(true){
            str = br.readLine().split("");
            if(str[0].equals("0")) break;
            result = 0;
            for(String str1 : str){
                result += Integer.parseInt(str1);
            }
            sb.append(result).append("\n");
        }
        System.out.print(sb);
    }
}
/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