python short topdown dp
\nclass Solution:\n    def stringCount(self, n: int) -> int:\n        \n        MOD = 10**9+7\n        @cache\n        def dp(i=0, s="leet"):\n            if i 
```\nclass Solution:\n    def stringCount(self, n: int) -> int:\n        \n        MOD = 10**9+7\n        @cache\n        def dp(i=0, s="leet"):\n            if i == n:\n                return not s\n            return (dp(i+1, s.replace("l", "")) + dp(i+1, s.replace("e", "", 1)) + dp(i+1, s.replace("t", "")) + 23*dp(i+1, s))%MOD\n        \n        return dp()\n```
['Dynamic Programming', 'Python3']