Coding in Java and please do not use startwith() opertation.

Read the whole input one line at a time and output each line if it is not a prefix of some previous line. (One string s is a prefix of another string t if t can be written as t=sx for some string x. For example, s='help' is a prefix of t='helpful' because 'helpful' = 'help' + 'ful'). Take care not to waste memory, so that your code stores the fewest number of lines possible. Hint: Consider what happens when you compare 'help' and 'helpful' using the usual ordering on Strings.