I am taking the petite shells edging from Knitting on the Edge and using it for a cardigan instead of a 1x1 rib. It says this:

Beg as a multiple of 5 sts plus 2 and end as a multiple of 4 sts plus 1

My cast on for the cardigan pattern is 165sts which IS a multiple of 4 sts plus 1 (the end result of the edging) but how do I figure out how many sts to cast on if I’m using this edging instead of what the pattern asks for???