Somebody can help me out.

In a spreadsheet I have column-A with x values and column-B with y
values.
In column-C I want the result that comes out of a matrix based on the
values from A and B.

Example;

Column-A Column-B Column-C Column-X
Y Z AA AB
row-1 temp: day:
matrixvalue: 0 1 2 3 4
row-2 20 1
f 10 a c d
e
row-3 10 3
d 20 f g h i
row-4 30 4
m 30 j k l m

In column C I need the formule that takes the value in column A for
lookup in column X and the value in column B for lookup in row one of
column Y-Z-AA-AB. De result of the horizontal/vertical is the letter
in column C.
Another issue is that if the value in column A is not the same as the
values in column X, then the formula has to look at the nearest by but
higher value. For example: value is 14 then you have to take 20.

Hopely some help from smart people.

regards,
Johan