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 main(){
  int N;
  cin>>N;
  int l=72;
  for(int i=1;i<=(N+1)/2;i++){
    int j=0;
    for(int k=i;k>0;k/=10)
      j+=k%10;
    for(int k=N-i;k>0;k/=10)
      j+=k%10;
    l=min(l,j);
  }
  cout<<l<<endl;
}