# L(G) = [G] + [O]
# G = [O]
# = GO
# L[E] = EO
# L[F] = [F] + [GO]
# F = [GO]
# = FGO
# L[B] = [B] + [FGO]
# B = [FGO]
# BF = [GO]
# BFG= [O]
# = BFGO
# L[C] = [C] + [EO]
# C = [EO]
# CE = [O]
# = CEO
# L[D] = [D] + [GO]
# D = [GO]
# DG = [O]
# = DGO
# L[A] = [A] + [BFGO] + [CEO] + [DGO]
# A = [BFGO] + [CEO] + [DGO]
# AB = [FGO] + [CEO] + [DGO]
# ABF= [GO] + [CEO] + [DGO]
# ABFC= [GO] + [EO] + [DGO]
# ABFCE= [GO] + [O] + [DGO]
# ABFCED = [GO] + [O] + [GO]
# ABFCEDG= [O] + [O] + [O]
# = ABFCEDGO
# L[G] = GO
# L[D] = DO
# L[E] = EGO
# L[F] = FO
# L[B] = [B] + [DO] + [EGO]
# B = [DO] + [EGO]
# BD = [O] + [EGO]
# BDE = [O] + [GO]
# BDEG = [O] + [O]
# = BDEGO
# L[C] = [C] + [DO] + [FO]
# C = [DO] + [FO]
# CD = [O] + [FO]
# CDF= [O] + [O]
# = CDFO
# L[A] = [A] + [BDEGO] + [CDFO]
# A = [BDEGO] + [CDFO]
# AB = [DEGO] + [CDFO]
# ABC = [DEGO] + [DFO]
# ABCD = [EGO] + [FO]
# ABCDE= [GO] + [FO]
# ABCDEG= [O] + [FO]
# ABCDEGF= [O] + [O]
# = ABCDEGFO
