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.util.Scanner;

public class Main {

	private void solve() {
		Scanner in = new Scanner(System.in);
		int N = in.nextInt();
		int min = Integer.MAX_VALUE;
		for(int i=1; i<N; i++) {
			int A = i;
			int B = N-i;
			int sum = 0;
			while(A>0) {
				sum += A % 10;
				A /= 10;
			}
			while(B>0) {
				sum += B % 10;
				B /= 10;
			}
			min = Math.min(min, sum);
		}
		System.out.println(min);
	}

	public static void main(String[] args) {
		new Main().solve();
	}
}