import java.util.Scanner;

class Main {

	public static void main(String[] args) {
		// TODO 自動生成されたメソッド・スタブ

		Scanner sc = new Scanner(System.in);

		int num = sc.nextInt();

		int a1=num/100;
		if(a1==1)
			num-=100;
		int a2=num/10;
		if(a2==1)
			num-=10;
		int a3=num/1;

		int sum=a1+a2+a3;
		System.out.println(sum);

		sc.close();
	}

}
/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