R1(config)#router ospf 1

R1(config-router)#network 192.168.13.0 0.0.0.255 area 1

R1(config)#router ospf 1

R1(config-router)#network 192.168.12.0 0.0.0.255 area 0

R2(config)#router ospf 1

R2(config-router)#network 192.168.12.0 0.0.0.255 area 0

R3(config)#router ospf 1

R3(config-router)#network 192.168.13.0 0.0.0.255 area 1

R3(config-router)#network 3.3.3.3 0.0.0.0 area 1