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: Accepted)

#include<iostream>
#include<algorithm>
#include<cmath>
#include<string>
#include<cstring>
#include<vector>
using namespace std;

int main()
{
	long long int i, j, k, l, m, sum,A,B,N;
	int flag = 0;
	sum = 0;
	cin >> N;
	if (N == 10 || N == 100 || N == 1000 || N == 10000 || N == 100000) {
		cout << "10" << endl;
	}
	else {
		while (N > 0) {
			sum += N % 10;
			N /= 10;
		}
		cout << sum << endl;
	}

    return 0;
}