Osemsmerovka č. 6 337 - What kind of room has no doors or windows?

E O L E N T I L C L D C N A M R A B P A A E H F R P D M M H C A N U R N A C S L I N H I A X R C V R R S N M E O A O D U R T E N L E T O M O A D V O U C H E R M B