input: from typing import List
  
  def findStrongestExtension(className: str, extensions: List[str]) -> str:
      """Given a class name and a list of extensions, determine the strongest extension based on the formula: strength = CAP - SM, 
      where CAP is the count of uppercase letters and SM is the count of lowercase letters in the extension's name.
      Return the class name followed by the strongest extension in the format: ClassName.StrongestExtensionName.
  
      >>> findStrongestExtension('MyClass', ['AA', 'Be', 'Cc'])
      'MyClass.AA'
      >>> findStrongestExtension('AnotherClass', ['ABC', 'DeF', 'GhIj'])
      'AnotherClass.ABC'
      >>> findStrongestExtension('ThirdClass', ['aBCd', 'eFGh', 'iJKL'])
      'ThirdClass.iJKL'
      """
      strongest_strength = float('-inf')
      strongest_extension = ""
      
      for ext in extensions:
          CAP = sum(1 for c in ext if c.isupper())
          SM = sum(1 for c in ext if c.islower())
          strength = CAP - SM
          if strength > strongest_strength:
              strongest_strength = strength
              strongest_extension = ext
              
      return f"{className}.{strongest_extension}"
output:     strongest_strength = float('-inf')
      strongest_extension = ""
      
      for ext in extensions:
          CAP = sum(1 for c in ext if c.isupper())
          SM = sum(1 for c in ext if c.islower())
          strength = CAP - SM
          if strength > strongest_strength:
              strongest_strength = strength
              strongest_extension = ext
              
      return f"{className}.{strongest_extension}"