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

	private void solve() {
		// 入力
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();
		sc.close();

		// 計算
		int min = Integer.MAX_VALUE;
		for (int A = 1; A < N; A++) {
			int B = N - A;
			int sumA = sumDigitsNumber(A);
			int sumB = sumDigitsNumber(B);
			if (sumA + sumB < min) {
				min = sumA + sumB;
			}
		}

		// 出力
		System.out.println(min);

		return;
	}


	private int sumDigitsNumber(int x) {
		int sum = 0;
		while(x > 0) {
			sum += x % 10;
			x /= 10;
		}
		return sum;
	}
}
