To make telephone numbers easier to remember, some companies use letters to show their telephone number. For example, using letters, the telephone number 438-5626 can be shown as GET LOAN. Write a program that prompts the user to enter a telephone number expressed in letters and outputs the corresponding telephone number in digits. If the user enters more than 7 letters, the process only the first 7 letters. also output the hyphen after the third digit. allow the user to use both uppercase and lowercase letters as well as spaces.