input: def find_nearest_vowel(word):
      """Given a word, the goal is to identify the closest vowel placed between
      two consonants, starting from the right side of the word (case sensitive).
  
      Vowels at the start and end positions are excluded. If no vowel meets
      the criteria, return an empty string.
  
      Assume the input string contains only English alphabet letters.
  
      Example:
      find_nearest_vowel("yogurt") ==> "u"
      find_nearest_vowel("FULL") ==> "U"
      find_nearest_vowel("quick") ==> ""
      find_nearest_vowel("ab") ==> ""
      """
output:     vowels = "AEIOUaeiou"
      n = len(word)
      
      for i in range(n - 2, 0, -1):
          if word[i] in vowels and word[i - 1] not in vowels and word[i + 1] not in vowels:
              return word[i]
              
      return ""