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 $N$.

Sample Input 1

100

Sample Output 1

18

For example, the sum of the digits in $99$ is $18$, which turns out to be the maximum value.

Sample Input 2

9995

Sample Output 2

35

For example, the sum of the digits in $9989$ is $35$, which turns out to be the maximum value.

Sample Input 3

3141592653589793

Sample Output 3

137