#952. Number of derangements (permutations where nothing stays in its place)
Find the **Number of derangements (permutations where nothing stays in its place)**.
### Input
One integer n (0 ≤ n ≤ 20).
### Output
Answer.
Examples
Input
9
Output
133496
Input
16
Output
7697064251745
💡 You can solve it with Python, JavaScript or blocks. Read the input line by line with input(). Don't print a question (like input("Number: ")). Print exactly what the output asks for, nothing more.