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. In some cases, to make a telephone number meaningful, companies must see more than seven letters. For example, 255-5466 can be displayed as CALL HOME, which uses eight letters.

Write a program that prompts the user to enter a telephone expressed in letters and outputs the corresponding telephone number in digits. If the user enters more than seven letters, then process only the first seven letters. Also output the - (hyphen) after the third digit. Allow the user to use both uppercase and lowercase letters as well as spaces between words.

* Java program free from syntax, logic and run time errors

* Used appropriate String and Character methods to handle blank spaces, digits, letters and others.

* Code optimisation: no unnecessary variables, if statements and counters.

* Shown with 3 Cases (at least one with blank spaces etc.). Descriptive block and inline comments included