DFS
A
H
12
A B 1
B C 1
C D 1
A E 10
E F 2
F G 3
G H 3
A I 1
I J 1
J K 1
K L 1
L H 1
12
A 1
B 1
C 1
D 1
E 1
F 1
G 1
H 1
I 1
J 1
K 1
L 1