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 S(int a){
  int sum=0;
  while(a>0){
    sum+=a%10;
    a/=10;
  }
  return sum;
}
int main(){
  int N,mi=45;
  cin>>N;
  for(int i=1;i<N/2+1;i++){
      mi=min(mi,S(i)+S(N-i));
  }
  cout<<mi<<endl;
}