Search for a specific cell based on two criteria
 

Okay,
Heres the challenge, I am attempting to insert a value into a
specific cell based upon a search of two columns to find the matching
criteria. To give an example, I am inserting a number into the "C"
column cell next to the matching "A" and "B" fields.
So if I was looking to insert the "total sales" for a branch of a
company(C value). I would look first for the month(A value), then the
branch name(B value) then insert fhe value in the column next to those
values.
To give a practical Example the Seattle branch has "4000" in sales for
january. The values of Seattle and January are already in the sheet. I
just need to insert 4000 into the column next to that

A B C
1 January Dallas ----
2 January Seattle <value needs to be inserted here
3 Januray Omaha ----
4 January New York ----

To make things easier, I already have code written to get the user
input of month and branch. So assuming that you would have those two
values stored in string variables, what would be the best approach to
tackling this?
Thanks in advance for any help given,

Rob