Add a 3rd lookup to a formula with 2 current matches

Hi all, a while back one of you gave me an awesome formula that pulls data from sheet 2 based on what was typed in A1 and A2 on sheet 1.

Well I ran into a snag, is there a way we can add a 3rd match in the formula. See the attached file.

I need to pull data from sheet 2 based on what is typed on sheet 1 in cell A1, A2 and A3.

Exp
Sheet 1, report to be printed
A1 = last name
A2 = first name
A3 = month

Sheet 2, data is held here
Need to pull data in column “M”


Thanks for the help

MS Excel 2002 SP3
Windows XP Pro

Two ways...

1) Expand the current formula in A1 to:
=INDEX(DATA!$M$1:$M$1999,MATCH(G4 & A4 & C4, INDEX(DATA!$A$1:$A$1999 & DATA!$I$1:$I$1999 & DATA!$J$1:$J$1999, 0), 0))


...or better:
2) Add a key column in column P of the DATA sheet. Put this formula in P2 and copy down:
=A2&I2&J2

Then change the A1 formula to the much simpler:
=INDEX(DATA!$M:$M, MATCH(G4 & A4 & C4, DATA!$P:$P, 0))

The second technique should expand to 10s of thousands of rows with no discernible performance slowdown.