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 <bits/stdc++.h>
using namespace std;
int main() {
    int n,ans = 9999999;
    scanf("%d",&n);
    for (int i = 1;i < n;i++) {
        int tmp = i,sum = 0;
        while (tmp) {
            sum += tmp%10;
            tmp /= 10;
        }
        tmp = n-i;
        while (tmp) {
            sum += tmp%10;
            tmp /= 10;
        }
        ans = min(ans,sum);
    }
    printf("%d",ans);
    return 0;
}