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 <bits/stdc++.h>
#define rep(i,n) for(int i=0;i<(int)(n);i++)
using namespace std;

int solve(int n) {
    int sum=0;
    while(n>0) {
    sum+=n%10;
    n/=10;
    }
    return sum;
}

int main() {
    int n,ans=0; cin >> n;
    for(int i=0;i<n;i++) {
        int a=i, b=n-i;
        int count=solve(a)+solve(b);
        ans=max(count,ans);
    }
    cout << ans << endl;
}