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,m;cin>>N;m=N;
  for(int A=1;A<N;A++){
    int a=A,b=N-A,S=0;
    while(a>0)S+=a%10,a/=10;
    while(b>0)S+=b%10,b/=10;
    m=min(m,S);
  }
  cout<<m<<endl;
}