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 (GCC 5.4.1) (judge verdict: Accepted)

#include <stdio.h>

int solve(int N)
{
    int ans = 0;
    do
    {
        ans += (N % 10);
        N /= 10;
    } while (N);
    return ans == 1 ? 10 : ans;
}

int main()
{

    int N, resposta;
    scanf("%d", &N);
    resposta = solve(N);
    printf("%d", resposta);

    return 0;
}