Multiple criteria sums

Hello,

I was hoping somebody could help me do this?
A B C
INC-001 05/2009 10
INC-002 07/2010 10
CTN-000 05/2009 10
INC-004 05/2009 10
INC-005 05/2009 10

In the spreadsheet above I want to put in ONE cell (e.g. D1). the sum of all the numbers in column C, where column A contains the letters INC, and column B contains 2009 (answer = 30). I know this can be done by adding another column and the IF function,and then using SUMIF but I would prefer not to do that if possible.

thanks in advance