Error in Formula column

I’m trying to count number from a range with the help of formula column with multiple conditions in it.

Formula is … RIGHT({Stamps},LEN({Stamps})-SEARCH("-",{Stamps},1))-LEFT({Stamps},LEN({Stamps})-SEARCH("-",{Stamps},1))+1

image

One can see where there is no range provided, it does not count. There is no IFERROR formula in this. Can I’ve some workaround to solve this?