I have a matrix with x axis and y axis

X axis has column headers of A, B, C
Y axis has row headers of D,E,F

If I enter A in cell a1 (B), and E in cell a2 (G), i want the intersect
value (8) to appear in cell a3

A B C
E 1 2 3
F 4 5 6
G 7 8 8

Thanks