import java.util.Scanner;

public class Main{
    public static void main(String[]argc){
        Scanner sc = new Scanner(System.in);
        outer:
        for(int k=0;;k++){
            int i = 0;
            String str = sc.next();
            int l = str.length();
            for(int j=0;j<l;j++){
                char a = str.charAt(j);
                int n = a - '0';
                if(l==1&&n==0) break outer;
                i+=n;
            }
            System.out.println(i); 
        }
    }
}

/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