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 $B$".