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 Python (2.7.6) (judge verdict: Accepted)

n=input()
if n<10:
	print n
	quit(0)
if str(n)[1:].count('9')==len(str(n)[1:]):
	print sum([ord(ch)-ord('0') for ch in str(n)])
else:
	print ord(str(n)[0])-ord('0')-1+9*len(str(n)[1:])