Write a program Permutations that takes an integer command-line argument \(n\) and prints all \(n\) ! permutations of the \(n\) letters starting at a (assume that \(n\) is no greater than 26). A permutation of \(n\) elements is one of the \(n\) ! possible orderings of the elements. As an example, when \(n=3\), you should get the following output (but do not worry about the order in which you enumerate them):

bca cba cab acb bac abc