part1 e------------------------0--------- b----0----0--3-1-01-0--3----------- g---0-0--2-2----------------------- d2--------------------------------- a---------------------------------- E---------------------------------- part 2 e0-3------------------0-0--3------- b---0--3-0--------0-3--0-0---3-1-0- g------------0-2------------------- d----------4----------------------- a---------------------------------- E---------------------------------- part 3 e------------------------0--------- b----0----0--3-1-01-0--3----------- g---0-0--2-2----------------------- d2-----------0--------------------- a--------0------------------------- E0---------------------------------