# Home

Score : $200$ points

### Problem Statement

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 $B$".

### Sample Input 1

15


### Sample Output 1

6


When $A=2$ and $B=13$, the sums of their digits are $2$ and $4$, which minimizes the value in question.

### Sample Input 2

100000


### Sample Output 2

10