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<cstdio>
#include<cstring>
#include<iostream>
#include<algorithm>
#include<queue>
#include<vector>
#include<map>
#include<set>
using namespace std;
typedef long long ll;
const int Inf=0x3f3f3f3f;
const int mod=1e9+7;
const int maxn=1e5+10;
int main(){
	int n;
	cin>>n;
	int Min=Inf;
	for(int i=1;i<=n/2;i++){
		int a=i,b=n-i;
		int sum=0;
		while(a){
			sum+=a%10;
			a/=10;
		}
		while(b){
			sum+=b%10;
			b/=10;
		}
		Min=min(Min,sum);
	}
	cout<<Min;
}