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 (3.4.3) (judge verdict: Wrong Answer)

lst_N = [int(c) for c in input()]

first = lst_N[0]
left = lst_N[1:]
if len(lst_N) == 1:
    print(lst_N[0])
elif set(left) == 9:
    print(sum(lst_N))
else:
    all_nine = "9" * (len(lst_N) - 1)
    lst_all_nine = [int(c) for c in all_nine]
    print((first-1) + sum(lst_all_nine))