Number items in a list that are NOT chosen

I have a list of names. For each name in the list, the cell to the left of the name will either be blank, or marked with an "X". In the column to the right of the list, I need a formula that will number the names in order starting with "1" at the top, but will EXCLUDE all of the names with "X" in the cell to the left. The result is that when I "choose" a name from the list by marking it with an "X", the name will be removed from the rankings.

For example, my top 5 names in the list will have numbers 1-5 marked in the column to the right, but when I put an "X" beside the 3rd name in the list, the cell to the right of the 3rd name will become blank, and the 4th name will then take the number 3, and all names below that will have their numbers change in order from 4 to the end of the list.

I'm attaching a file that shows what I want the result to look like, but I need a formula to make it work.

Thanks.

This worked! Thank you!

I decided to add some complexity to this, which lead me to modify your formula to :

=IF(B2="",COUNTBLANK($B$2:B2),"")

This is because I changed the criteria from "X" to any number, so I needed the formula to simply count the blank cells.

Now have another question that I'm hoping can be solved with a simple formula rather than a bunch of nested vlookups:

I've created a sheet called "Names" where I have created 5 separate lists of names. Each name is unique (no duplicate names). On my sheet named "Development," I want column B to search the entire "Names" sheet for the name in Column C and return the data in the "Order #" column (to the right of the name) from the "Names" tab (or an blank cell if Order # is blank).

Thanks.