Two routers, R1 and R2, are connected back-to-back over a single Ethernet link in OSPF area 0. An engineer notices that adjacency forms correctly, but a DR and BDR election occurs on the segment, adding unnecessary election overhead and a slightly slower convergence when the link flaps. The engineer wants to eliminate the DR/BDR election on this point-to-point Ethernet link while keeping OSPF adjacency intact. What should be configured on both interfaces?