Fully white material under any light incidence angle

Hi all

I am trying to get a material that renders white (diffuse) under any amount of light independently of the light incidence angle, and black if it is in the shadow (no GI). That is, white or black, but not grey whatsoever. It was possible to be done in UDK using the custom lighting input node of the material, but now in UE4 it seems that we can’t implement any kind of custom lighting.

Any ideas of how can it be done?