I have two workbooks. Lets call them A and B

I need to count the # of times a certain value shows up in workbook b and put that in workbook a. I can do it with a single value, i.e. CO

but cant figure out two values...

I just need to count the # of times CO is used when then room size=2 or 1 or 4 or 3 etc and put that info into worksheet A. Also if possible I need to seperate rooms that are size 3 or 4 but within the 4000 room #'s.

Do I use sumif or sumproduct?

ROOM TYPE SIZE
1203 CO 2
2304 CO 4
8211 MW 1
4303 MW 3
4501 TNT 4
4207 TNT 4