I have this sysex string and need to find out how the last byte (18) before F7 was calculated.

F0 07 00 78 09 00 67 00 01 00 00 18 00 45 71 75 61 6C 00 01 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 3F 79 60 18 F7


thanks