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 a){
  int k=0;
  while(a>0)k+=a%10,a/=10;
  return k;
}
int main(){
  int n,a=1,m=99;
  cin>>n;
  for(;a<n;a++)m=min(m,f(a)+f(n-a));
  cout<<m;
}