Problem:
Score : 200 points

Problem Statement

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".

Sample Input 1

15

Sample Output 1

6

When A=2 and B=13, the sums of their digits are 2 and 4, which minimizes the value in question.

Sample Input 2

100000

Sample Output 2

10

Solution in Java8 (OpenJDK 1.8.0) (judge verdict: Accepted)

import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();
		sc.close();
		int min = 10 * N;
		for(int A = 1; A <= N / 2; A++) {
			int B = N - A;
			min = Math.min(min, digitsSum(A) + digitsSum(B));
		}
		System.out.println(min);
	}
	static int digitsSum(int n) {
		int ret = 0;
		String s = Integer.toString(n);
		for(int i = 0; i < s.length(); i++) {
			ret += Integer.parseInt(s.substring(i, i + 1));
		}
		return ret;
	}
}