Counting Distinct Bib Numbers

You are given an integer k. In this problem, you need to calculate the number of distinct bib numbers of length k that can be formed using the digits 1 through 9. Each bib number must have its digits arranged in strictly increasing order.

This is equivalent to choosing k distinct digits from 9 digits, and the answer is given by the combination formula:

\( C(9, k) = \frac{9!}{k!(9-k)!} \)

Your program should read the input from stdin and write the output to stdout.

inputFormat

The input consists of a single integer k (1 ≤ k ≤ 9), read from stdin.

outputFormat

Output the number of distinct bib numbers that can be formed of length k. The answer should be output to stdout.

1

9