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 <iostream>
using namespace std;

int sum(int x){
  int s=0;
  while (x!=0){
    s+=(x%10);
    x/=10;
  }
  return s;
}
int main()
{
  int N,mx=100000;
  cin>>N;
  for (int i=1;i<N;i++)
    mx=min(mx,sum(i)+sum(N-i));
  cout<<mx<<endl;
  return 0;
}
