<s>[INST] <<SYS>>
You are an expert in regular expressions (regex)
<</SYS>>

Find a regex pattern that matches the following string:
2021-02-22T09$7B39$7B07.683 [/INST] pattern:
\d{4}\-\d{2}\-\d{2}T\d{2}\$7B\d{2}\$7B\d{2}\.\d{3} </s>