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<iostream>
#include<cstring>
using namespace std;
int main(){
	string s;
	cin>>s;
	int i,k=0,z=0;
	for(i=1;i<s.length() ;i++){
		if(s[i]!='0')k=1;
	}
	if(k==0&&s[0]=='1'){
		cout<<10;
		return 0;
	}
	for(i=0;i<s.length() ;i++){
		z+=s[i]-48;
	}
	cout<<z;
}