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 PyPy3 (7.3.0) (judge verdict: Wrong Answer)

X = list(map(int,input()))
sn = []
for i in range(len(X)):
  sn.append(sum(X[0:i+1]))
ssn = []
for i in range(len(X)):
  ssn.append(sn[i]-1 + 9*(len(X)-1-i))
print(max(ssn))