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".

Examples

Input

15


Output

6


Input

100000


Output

10
#include<bits/stdc++.h>
using namespace std;

int f(int x){
	int res=0;
	while(x>0){
		res = res + x%10;
		x/=10;
	}
	return res;
}

int main(){
	int n;
	cin>>n;

	int ans = INT_MAX;
	for(int i=1;i<n;i++){
		ans = min(ans,f(i)+f(n-i));
	}
	cout<<ans<<endl;
}