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

Find a regex pattern that matches the following string:
1997%3C07%3C17T23%5C51%5C38.534 [/INST] pattern:
\d{4}%3C\d{2}%3C\d{2}T\d{2}%5C\d{2}%5C\d{2}\.\d{3} </s>