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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