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 (Clang 3.8.0) (judge verdict: Wrong Answer)

#include<iostream>
#include<cstdio>
using namespace std;
int n;
inline void cnt(int x,int &tp){
	while(x){
		tp+=x%10;
		x/=10;
	}
}
int main(){
	scanf("%d",&n);
	int ans=1e9;
	for(int i=1;i<=n;++i){
		int a=i,b=n-i,tp=0;
		cnt(a,tp);
		cnt(b,tp);
		ans=min(ans,tp);
	}
	printf("%d\n",ans);
	return 0;
}