Convert Reactome Protein IDs to Pathway IDs?

I have a list of about 50k 'Protein IDs' from Reactome. Is there a simple way to get all the corresponding 'Pathway IDs' for each protein? What is the best service to use? (I'm guessing I can use the Reactome API, but I don't necessarily want to hit that 50k times...).

Protein IDs from reactome look like this:

R-HSA-49155R-HSA-199420

The corresponding Reactome 'Pathway IDs' for those Protein IDs would be:

R-HSA-49155  R-HSA-110331R-HSA-49155  R-HSA-110330R-HSA-49155  R-HSA-110357R-HSA-199420 R-HSA-1660499R-HSA-199420 R-HSA-202424R-HSA-199420 R-HSA-199418