Problem:
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

Solution in Scala (2.11.7) (judge verdict: Wrong Answer)

object Main extends App {
	import scala.math._

	val n = scala.io.StdIn.readLong
	val a = log10(n).toInt

	var test = 1L

	for(i<-0 until a){
		test = test * 10L
	}

	var ans = (n/test - 1)

	for(i<-0 until a){
		ans = ans + 9L
	}

	println(ans)


}