Write a method that returns a string constructed from two characters. The first character (a) will appear totA number of times. The second character (b) will appear after every freqB occurrences of the first character, except that this character will never appear at the very end of the string. Look at the test data for examples. You may NOT use ANY string methods! (None are needed). Obviously you will need to work with strings, but you cannot use any string METHODS such as .length, .substring, etc.