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.*;

public class Main {
    public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
        
        int n = sc.nextInt();
        
        int min = Integer.MAX_VALUE;
        
        for(int i = 1; i < n; i++){
            int a = n - i;
            int b = i;
            
            min = Math.min(min, sum(a) + sum(b));
        }
        
        System.out.println(min);
    }
    
    public static int sum(int a){
        String str = String.valueOf(a);
        int sum = 0;
        for(char c : str.toCharArray()){
            sum+=c-'0';
        }
        return sum;
    }
}