A survey of 120 people was conducted to determine who have watched from the three different television networks. The results are shown as follows: (a) 55 people watched ABN; (b) 30 people watched GMS; (c) 40 people watched TBA; (d) 10 people watched ABN and TBA; (e) 12 people watched ABN and GMS; (f) 8 people watched GMS and TBA; (g) 5 people watched ABN, GMS and TBA. How many of the 120 people did not watch any of the three television networks?​