You have two Strings, s and t, and you want them to be equal. You can change individual letters in the Strings, but you cannot add or remove letters. In a single move, you can change any one letter in one String to the letter that comes directly before or after it in the alphabet. The alphabet wraps around, so you can also change 'a' to 'z' or 'z' to 'a'. You want to make the two Strings equal using the minimum possible number of moves. Return the resulting String. If there are multiple answers, return the one that comes earliest alphabetically.