Decipher the quote from Philip Pullmans "His Dark Materials":
Erh csy wlepp orsa xli xvyxl, erh xli xvyxl wlepp qeoi csy jvii.
The same letters correspond to the same in the phrase, different letters
correspond to different. We know that no original letters stayed in
place, meaning that in places of e,r,h there was surely something
else.