Problem Statement

Find the maximum possible sum of the digits (in base $10$) of a positive integer not greater than $N$.

Constraints

• $1\leq N \leq 10^{16}$
• $N$ is an integer.

Input

Input is given from Standard Input in the following format:

N

Output

Print the maximum possible sum of the digits (in base $10$) of a positive integer not greater than $N$.