Lost_In_Transliteration

We found a service that converts Greek characters to Latin. It seems simple: ΕΛΛΑΣ becomes ELLAS.

However, our logs show some very strange outputs. The service is flawed, but we think it's by design. There's a secret hidden in the way it handles the characters. Your job is to find what's "lost" in the transliteration. The flag is in there somewhere. Good luck.