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).

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".

Constraints

• 2 ≤ N ≤ 10^5
• N is an integer.

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

见题面 Input 部分

见题面 Output 部分