Kata

This is the simple version of Shortest Code series. If you need some challenges, please try the challenge version

Task:

Every uppercase letter is Father, The corresponding lowercase letters is the Son.

Give you a string s, If the father and son both exist, keep them. If it is a separate existence, delete them. Return the result.

For example:

sc("Aab") should return "Aa"

sc("AabBc") should return "AabB"

sc("AaaaAaab") should return "AaaaAaa"(father can have a lot of son)

sc("aAAAaAAb") should return "aAAAaAA"(son also can have a lot of father ;-)

Series:

• Bug in Apple
• Father and Son
• Jumping Dutch act
• Planting Trees
• Give me the equation
• Find the murderer
• Reading a Book
• Eat watermelon
• Special factor
• Guess the Hat
• Symmetric Sort
• Are they symmetrical?
• Max Value
• Trypophobia
• Virus in Apple
• Balance Attraction
• Remove screws I
• Remove screws II
• Regular expression compression
• Collatz Array(Split or merge)
• Tidy up the room
• Waiting for a Bus