mylist=[]   #Bulunan karakterler bu listeye atilacak.
sentence = "LLLlLLLIIIiIIINNNnNNNKKKkKKKEEEeEEEDDDdDDDLLLlLLLIIIiIIISSSsSSSTTTtTTT"



for index,char in enumerate(sentence):
       if char.islower() and sentence[index-3:index].isupper() and sentence[index+1:index+4].isupper():
                   mylist.append(char)


print ''.join(mylist) #listeyi string yapmaca