import java.util.Scanner;

class Main {
    public static void main(String[] args) {
        Scanner scan = new Scanner(System.in);
        int a = Integer.parseInt(scan.next());

        int b = a % 10;
        int c = a / 10 % 10;
        int d = a / 100 % 10;

        System.out.println(b + c + d);
    }
}
/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