思考题for Ep.11
Lunatic Walking
Orange Boy loves walking. One day, he wanna walk from
the boy can walk in three types:

from
to by costing A yuan 
from
to by costing B yuan 
from
to or by costing C yuan
There are some exchange stations at
What's the minimal cost from start to end???!!?!
Examples
Input
A,B,C=2,3,4
(1,1) > (4,3)
Stations:
(3,3,1)
(2,2,3)
(100,100,100)
Output
6
Explain
Path is this:
(1,1) > (2,2) > (3,3) > (4,3)
Cost=4+4+213=6
Constriants
Subtask 1(100%):