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)

N = input()

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

if len(N) -1 == N.count("9"):
    sd = 0
    N = int(N)
    while N > 0:
        sd += N % 10
        N //= 10
    print(sd)
    exit()
if N[0] == 1:
    print(9 * (len(N) - 1) + 8)
else:
    print(int(N[0])-1 + 9 * (len(N) - 1))