Write a method that returns how many different strings can be made from rearranging the letters in the input parameter string. As preconditions, you may assume that the string will contain at least one character, that there will be no repeated characters, the string will have no more than ten characters, and that the string will only contain lower-case letters. For example, "abc" has six different arrangements possible: "abc", "acb", "bac", "bca", "cab", and "cba". Look at the test data for more examples.