(Caesar Cipher)

The following ciphertext results from a Caesar cipher (and removing all spaces and splitting the letters into blocks of 5): "OZYEW PEDNS ZZWTY RTYEP CQPCP HTESJ ZFCPO FNLET ZY" Determine the shift, and recover the plaintext by hand (briefly describe how you did it, you don't have to use brute force!).

Please explain