Trust Me, I'm An Engineer.
Numbering Rule (Nikon) : [ YLS_XXXX(_Y) ]
XXXX : Photo count.
Y : Post-production state. (M: by Gaku, m: by others.)
Numbering Rule (Panasonic) : [ PXXX0YYY(_Z) ]
XXX: (Photo count - 100) x 1000.
YYY: Photo count.
Z : Post-production state. (M: by Gaku, m: by others.)