class Node:
    def __init__(self):
        self.char = {}
        self.is_end = False

class Trie:
    def __init__(self):
        self.root = Node()
        
    def insert(self, word: str) -> bool:
        # Return True if inserted; False if word is a prefix or has a prefix
        curr_node = self.root
        for c in word:
            if c not in curr_node.char:
                curr_node.char[c] = Node()
            curr_node = curr_node.char[c]
            if curr_node.is_end:
                # An existing word is a prefix of the current word
                return False
        if curr_node.char:
            # The current word is a prefix of an existing word
            return False
        curr_node.is_end = True
        # The word was successfully inserted
        return True

def noPrefix(words: list[str]) -> None:
    trie = Trie()
    for word in words:
        if not trie.insert(word):
            print('BAD SET')
            print(word)
            return
    print('GOOD SET')