you run the following command in R1,
R1#show ip protocols
Routing Protocol is "eigrp 100"
  Outgoing update filter list for all interfaces is not set
  Incoming update filter list for all interfaces is not set
  Default networks flagged in outgoing updates
  Default networks accepted from incoming updates
  EIGRP metric weight K1=1, K2=0, K3=1, K4=0, K5=0
  EIGRP maximum hopcount 100
  EIGRP maximum metric variance 1
  Redistributing: eigrp 100
  EIGRP NSF-aware route hold timer is 240s
  Automatic network summarization is in effect
  Automatic address summarization:
    192.168.1.0/24 for FastEthernet0/0
      Summarizing with metric 40512000
    172.16.0.0/16 for Serial0/0/1
      Summarizing with metric 28160
  Maximum path: 4
  Routing for Networks:
    172.16.1.0/24
    192.168.1.0
  Routing Information Sources:
    Gateway           Distance    Last Update
    (this router)           90    00:09:38
    Gateway           Distance    Last Update
    192.168.1.102           90    00:09:40
Distance: internal 90 external 170
Which networks are being automatically summarized by EIGRP with metric 28160?