0 -> n
n -> 0
n -> 0
0 -> n
0 -> a
a -> 0
a -> 0
0 -> a
a -> 0
0 -> a
0 -> m
m -> 0
m -> 0
0 -> m
0 -> c
c -> 0
0 -> c
c -> 0
c -> 0
0 -> c