Oh dear, I guess you have cracked the two caesar cryptos...
This one is more difficult. Although a simple substitution is easily cracked...
Again the characters are limited to A-Z... But I think I can come up with a 256 version again.

Enjoy!

GA LYC HEJMOYLA ORT ARU SHZ NCHT LYMW JA FNMCZT M HJ MJPNCWWCT ICNA KCEE TRZC ARUN WREULMRZ QCA MW ZNNHNOGGNRGY LYMW EMLLEC SYHEECZOC KHW ZRL LRR YHNT KHW ML