Real-life problem. Timetable

Draw the tour graph for the following routes for refuse vehicles collecting from industrial sites A, .., R, and use it to find the minimum number of days needed to ensure that no place is visited more than once on the same day. What is the corresponding vertex decomposition?
  • route 1 sites A, B, C and D route 2 sites B, E, F, G
  • route 3 sites B, H, I route 4 sites B, F
  • route 5 sites E, 6, J route 6 sites G, K, L
  • route 7 sites L, M, N route 8 sites K, N
  • route 9 sites A, H, O, I route 10 sites 0, P
  • route 11 sites C, P, O route 12 sites C, O, R