Keep a concrete character regular expressioon

i need to keep only two characters of a field but i dont know how to do it.

I would like to keep the second and third character of the server name, which indicates the country code, for example T52EDFS011 (52).
i'm new with regular expressions....

Thanks in advanced!

One way it can be achieved in Kibana is by; using static lookup in the field in giving country codes for each value.

thank you, finally i can doit with this: