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 C++14 (GCC 5.4.1) (judge verdict: Wrong Answer)

#include <iostream>
#include <string>
#include<math.h>
using namespace std;

int main() {
	int N, A, B,sumA=0,sumB=0,min;
	cin >> N;

	B = 1;
	A = N - B;
	while (true) {
		sumA += A % 10;
		A /= 10;
		sumB += B % 10;
		B /= 10;
		if (A == 0 && B == 0) break;
	}
	min = sumA + sumB;
	cout << min << endl;

	for (int i = 2; i < N; i++) {
		B = i;
		A = N - B;
		sumA = 0, sumB = 0;
		while (true) {
			sumA += A % 10;
			A /= 10;
			sumB += B % 10;
			B /= 10;
			if (A == 0 && B == 0) break;
		}
		if (min > sumA + sumB)min = sumA + sumB;

	}
	cout << min << endl;
}