This problem is a programming version of Problem 56 from projecteuler.net
A googol is a massive number: one followed by one-hundred zeros. is almost unimaginably large: one followed by two-hundred zeros. Despite their size, the sum of the digits in each number is only 1.
Considering natural numbers of the form, , where , what is the maximum digital sum?
Input Format
Input contains an integer
Constraints
Output Format
Print the answer corresponding to the test case.
Sample Input
5
Sample Output
13
Explanation
and , which is the maximum digital sum for this range.