Split ORDp for AutoLandscape

Hi there,

I followed an auto landscape material tutorial, but since then, quixel bridge doesn’t give a roughness texture, but an ORDp. How can I do this and also use ambient occlusion?
Here is the material function (roughness section):

There is a parameter for the roughness, but it doesn’t split RGB.
Any ideas on how to do this?
Thanks.