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

Find a regex pattern that matches the following string:
1999%3D12%3D30+18$7E50$7E06.211 [/INST] pattern:
\d{4}%3D\d{2}%3D\d{2}\+\d{2}\$7E\d{2}\$7E\d{2}\.\d{3} </s>