Parsing a String

Create a program that takes input from the user and converts it into a list with a string for each word in the input.

The program should then print each word on a separate line in reverse order.

Next the program asks for a single word.

Check to see if this new word occurred in the original list of words. Print a message telling whether the word given was valid or not.

Now join all the words from the original input with an underscore between them and print that string.