Calculate number of orders per month in calculated column

[Legacy 221383]

Hi,

I have a problem with PowerPivot that I cannot seem to solve...
This is the PowerPivot table that I have:

Order ID	Customer	Month
1	1000	1
2	2000	1
3	1000	1
4	3000	1
5	2000	1
6	1000	1
7	3000	1
8	1000	2
9	2000	2

<tbody>
</tbody>

What I need is a column that tells me Order ID 1 is customer 1000's 1. order in month 1 and so forth... This should then look like this:

Order ID	Customer	Month	Order in month
1	1000	1	1. order
2	2000	1	1. order
3	1000	1	2. order
4	3000	1	1. order
5	2000	1	2. order
6	1000	1	3. order
7	3000	1	2. order
8	1000	2	1. order
9	2000	2	1. order

<tbody>
</tbody>

In Excel I would use the following formula in column D: =COUNTIFS($B$2:$B2;B2;$C$2:$C2;C2) &". order" to get my desired result. But I cannot figure out how to get this done in DAX so that I can have a calculated column in my PowerPivot table.

Thank you very much for any help to get me closer to my goal!