Build, test, and debug regular expressions
Matches a Russian SNILS (pension insurance account number) in its standard formatted layout: three groups of three digits separated by hyphens, followed by a space and two trailing digits (e.g., 123-456-789 00), 11 digits in total. The ^ and $ anchors combined with the multiline flag validate each line independently, making it useful for checking SNILS entries in lists, logs, or documents. Note it validates format only and does not verify the checksum.