Paaaa Glaaa - 2008-11-25

How can I decode this string?

string tmp = "?UTF-8?Q?=C5=BC=C3=B3=C5=82=C4=87?=";

SharpMimeTools.rfc2047decode(tmp);

returns something like this:

��������

but it should return

żółć

What should I do?