S
bSC
bbSCC
bbaCC either of the C’s goes to epsilon
S S
| |
+-------+-----------+ +-------+-----------+
| | | | | |
| S C | S C
| | | | | +++
| +--+----+ | +--+----+ | |
| | S C | | S C | S
| | | +++ | | | | | |
| | | | | | | | | |
| | | | S | | | | |
| | | | | | | | | |
b b a c a b b a c a