In a woorkbook I have two sheets

In one sheet I got a tabel With exchange rates one coulom per month and one
row per currency
January February
USD XXX XXX
Euro XXX XXX

In the other sheet I am standing i cell D4 where I like to get the correct
exhange rate. I got one cell (B4) with the months name an an other (C4) with
the name of the currency.

Do any have an idear ?
--
Palle korsholm