input: def editDistance(string1: str, string2: str) -> int:
      """Compute the edit distance between two strings.
      >>> editDistance("kitten", "sitting")
      3
      """
output:     if len(string1) == 0:
          return len(string2)
      if len(string2) == 0:
          return len(string1)
      
      if string1[0] == string2[0]:
          return editDistance(string1[1:], string2[1:])
      
      insert = editDistance(string1, string2[1:])
      delete = editDistance(string1[1:], string2)
      replace = editDistance(string1[1:], string2[1:])
      
      return 1 + min(insert, delete, replace)