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<vector>
#include<algorithm>
#include<functional>
#include<queue>
#include<stack>
#include<set>
#include<climits>
#include<cstdlib>
#include<cmath>
#include<string>

using namespace std;

#define INF 1 << 29
#define LL long long int

int main(){
    cin.tie(0);
    ios::sync_with_stdio(false);

    int n;

    cin >> n;

    int min = INF;

    for(int i = 0; i < n; i++){
        int tmpa,tmpb;
        tmpa = i;
        tmpb = n - i;
        int total = 0;
        while(tmpa > 0){
            total += tmpa%10;
            tmpa /= 10;
        }
        while(tmpb > 0){
            total += tmpb%10;
            tmpb /= 10;
        }
        if(total < min){
            min = total;
        }
    }

    cout << min << endl;

    return 0;
}