Please help WITHOUT using the array function - using JAVA

To make telephone numbers easier to remember, some companies user 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 might use more than seven letters. For example 225-5466 can be displayed as CALL HOME, which uses eight letters. Write a Java 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 that seven letters (spaces do not count), then process only the first seven letters and ignore the rest. Your program should also output the - (hyphen) after the third digit. Allow the user to use uppercase and lowercase letters, as well as spaces between the words Hint1: You can use the charAt method of the class String to extract each character. For example, if str refers to your String, then the expression str.charAt(i returns the character at the ith position. Recall that in a String, the position of the first character is 0 Hint2: You can use the toUpperCase or toLowerCase method of the class String to convert all chars in the String to upper or lower. If the user enters: Get Loan Your program will output: 438-5626