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.FileNotFoundException;
import java.util.Arrays;
import java.util.Scanner;

public class Main {
	public static void main(String[] args) throws FileNotFoundException {
		new Main().run();
	}

	void run() throws FileNotFoundException {
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();
		int ans = Integer.MAX_VALUE / 3;
		for (int A = 1; A <= N - 1; ++A) {
			int B = N - A;
			ans = Math.min(ans, cnt(A) + cnt(B));
		}
		System.out.println(ans);
	}

	int cnt(int a) {
		int ret = 0;
		while (a > 0) {
			ret += a % 10;
			a /= 10;
		}
		return ret;
	}

	void tr(Object... objects) {
		System.out.println(Arrays.deepToString(objects));
	}
}
