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)

# もし全部が9なら、9*N
# 一桁目が9以外なら (一桁目-1) + (len(N)-1 * 9)
# 一桁目が9なら　一桁目が8 + len(N)-1 * 9
S = (input())

if S.count("9") == len(S):
    print(len(S)*9)

elif len(S) == 1:
    print(int(S))

elif S.count("9") == (len(S)-1):
    print((int(S[0])) + (len(S)-1)*9)

elif S[0] == "9":
    print(8 + ((len(S)-1)*9))
else:
    print((int(S[0])-1) + (len(S)-1)*9)