Task 3: Permutation.
Permutations in mathematics are the ways of picking several items from a large group,
where order matters. For example, there are 12 ways to pick 2 items with different orders
from a group of 4 items. In mathematics, the number of permutations of picking k items
with different orders from a group of n items is denoted as $P^n_k$, $^nP_k$, or $P(n,k)$.
$\frac{n!}{(n-k)!}$
Write a function named getNumberOfPermutations(n, k) for computing $P^n_k$ using following
header:
def getNumberOfPermutations(n, k):
Write a test program that prompts the user to enter n and k and displays $P^n_k$ as shown in the
following sample run:
<Output>
Enter n: 4
Enter k: 2
The P(n, k) is 12
<End Output>
<Output>
Enter n: 500
Enter k: 45
The P(n, k) is
3690091613881336854967574813004580538477191402942308559040200319586680502
859734621537150301718903887006531584000000000000
<End Output>
