Hi everyone, I'd like to ask you about fees in Greek trains with OSE. I'm gonna travel from Athens to Kalambaka with FIP coupon (that one with date needing to be filled to the windows). Is there any need to buy some additional ticket? Or do I have a right to get discount since I'll be 17 when I get there. I found some information on the internet but I'm afraid I haven't clearly understood it. Thank you guys for the answers, it's going to be my first time traveling in Greece on my own.