Python fast and simple
\nclass Solution:\n    def greatestLetter(self, s: str) -> str:\n        from string import ascii_lowercase as al, ascii_uppercase as au\n        for i in range
```\nclass Solution:\n    def greatestLetter(self, s: str) -> str:\n        from string import ascii_lowercase as al, ascii_uppercase as au\n        for i in range(len(al)-1,-1,-1):\n            if al[i] in s and au[i] in s:\n                return au[i]\n        else:\n            return \'\'\n```
['Python', 'Python3']