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 n,ret;
int sum(int m){
	int r=0;while(m)r+=m%10,m/=10;return r;
}
int main(){
	cin>>n;ret=sum(n-1)+1;
	for(int i=1;i<n;i++)ret=min(ret,sum(i)+sum(n-i));
	cout<<ret<<endl;
}