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;
 
class Main {
	int n;
	
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
		Main m = new Main(sc);
		m.solve();
		sc.close();
	}
	Main(Scanner sc){
		n = sc.nextInt();
	}
	void solve(){
		int min = Integer.MAX_VALUE;
		int sum;
		int i;
		for(int a=1;a<n;a++){
			sum = 0;
			i = a;
			while(i>0){
				sum += i%10;
				i /= 10;
			}
			i = n-a;
			while(i>0){
				sum += i%10;
				i /= 10;
			}
			min = Math.min(min, sum);
		}
		System.out.println(min);
	}
}