393. Exploring Good Strings
A Good String is defined as a string that consists only of vowels (a, e, i, o, u). Given a string S, find and output the length of the longest substring of S that is also a Good String. **Note**: The time limit for this problem is 1 second, so it is important to optimize your substring computation.
A string 'S' containing characters
Output a single positive integer N, where N represents the length of the longest sub-string of S that is also a Good String.
String length < 10^5