Regex

[A-Z] - Any uppercase character in that range.
[a-z] - Any lowercase character in that range.
[0-9] - Any number.
[Cybar] - Only Cybar.
[^Berlin] - Not any those letters: "Berlin".
{N} - Number of times.
{N,} - Number of times or above.
{N,N1} - Number of times between N and N1.
^ - Start of a line.
$ - End of a line.
\w - Any character like uppercase, lowercase, numbers and underscore.