# A transformation sequence from word beginWord to word endWord using a dictionary wordList is a sequence of words such that:

# The first word in the sequence is beginWord.
# The last word in the sequence is endWord.
# Only one letter is different between each adjacent pair of words in the sequence.
# Every word in the sequence is in wordList.
# Given two words, beginWord and endWord, and a dictionary wordList, return the number of words in the shortest transformation sequence from beginWord to endWord, or 0 if no such sequence exists.


# Example 1:

# Input: beginWord = "hit", endWord = "cog", wordList = ["hot","dot","dog","lot","log","cog"]
# Output: 5
# Explanation: One shortest transformation is "hit" -> "hot" -> "dot" -> "dog" -> "cog" with 5 words.
# Example 2:

# Input: beginWord = "hit", endWord = "cog", wordList = ["hot","dot","dog","lot","log"]
# Output: 0
# Explanation: The endWord "cog" is not in wordList, therefore there is no possible transformation.
