Takahashi has two positive integers A and B.

It is known that A plus B equals N. Find the minimum possible value of "the sum of the digits of A" plus "the sum of the digits of B" (in base 10).

Constraints

* 2 ≤ N ≤ 10^5
* N is an integer.

Input

Input is given from Standard Input in the following format:


N


Output

Print the minimum possible value of "the sum of the digits of A" plus "the sum of the digits of B".

Examples

Input

15


Output

6


Input

100000


Output

10
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

public class Main {
	public static void main(String[] args) throws NumberFormatException, IOException {
		// TODO 自動生成されたメソッド・スタブ
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));


		int n = Integer.parseInt(br.readLine());

		int min = Integer.MAX_VALUE;
		for(int i = 1; i < n - 1; i++){
			int a = sumOfDigits(i);
			int b = sumOfDigits(n - i);

			if(a + b < min){
				min = a + b;
			}
		}
		if(n == 2){
			min = 2;
		}

		System.out.println(min);
	}

	static int sumOfDigits(int x){
		int result = 0;
		while(x > 0){
			result += x%10;
			x /= 10;

		}

		return result;
	}

}
