how to superimpose three matrix

A = [ nan 2 1; nan nan 4; 8 nan 7] B = [9 nan nan;nan 4 nan;nan nan nan] C = [nan nan nan;3 nan nan; nan 5 nan] result =[ 9 2 1 ;3 4 4;8 5 7)

Answer 1

[Azzi Abdelmalek]

out=max(A,B)
out=max(out,C)

Answer 2

[Iain]

One method:

 ActualMatrix(:,:,1) = A;
 ActualMatrix(:,:,2) = B;
 ActualMatrix(:,:,3) = C;

 AcutalMatrix(isnan(ActualMatrix)) = 0;

 answer = sum(ActualMatrix,3);