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Contest: Task: Related: TaskB

Score : $300$ points

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