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 {
    private static int sum(int x) {
        int ans = 0;
        for (; x > 0; x /= 10) {
            ans += (x % 10);
        }
        return ans;
    }

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int N = sc.nextInt();
        int ans = Integer.MAX_VALUE;

        for (int i=1; i<N; i++) {
            int A = i;
            int B = N - A;

            int sumOfAB = sum(A) + sum(B);
            if (sumOfAB < ans) {
                ans = sumOfAB;
            }
        }

        System.out.println("" + ans);
    }
}