NODES
A
B
C
D
E
F
G
H
I
J
K
L
M
N
EDGES
A B 20
A G 3
A C 2
C H 5
B E 18
E J 1
B I 2
F I 4
D F 3
B D 5
D K 16
K L 3
M N 4
L N 2 
K M 1