0 a 1 a R 1 a 1 a R 1 b 1 b R 1 c 2 c R 2 a 3 a R 3 a 3 a R 3 b 3 b R 0 b 4 b R 4 a 4 a R 4 b 4 b R 4 c 5 c R 5 b 6 b R 6 a 6 a R 6 b 6 b R 3 # 7 # S 6 # 7 # S