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Zadanie Komiwojażer Bajtazar (kom)
Byteasar the Travelling Salesman
Memory limit: 32 MB
A salesman Byteasar works hard travelling over Byteotia. In past times travelling salesmen could choose on their own towns they wanted to visit and order to do so, but those times are now gone forever. From the time the Central Controlling Office for Travelling Salesmen was established every salesman gets from the Office a list of towns to visit and the order of his tour. As it usually happens with central offices, the imposed order of visiting towns has not much in common with an optimal order. Before leaving for his tour Byteasar would like to know at least how much time it will take him to visit all the towns. It is your task to compute this.
The towns of Byteotia are numbered from 
to 
. The
capital of Byteotia has the number 
, and this is the place Byteasar
starts on his journey from. The towns are connected by a network of two-way
roads. A trip between two towns directly connected by a road always takes 1 unit
of time. From the capital one can reach any other Byteotian town. However, the
road network had been designed very thriftily, so the roads never form cycles.
Task
Write a program which:
- reads from the standard input the description of the road network in Byteotia and the list of towns that Byteasar has to visit,
- computes the total time of Byteasar's trip,
- writes the result to the standard output.
Input
In the first line of the standard input there is one integer 
equal
to the number of towns in Byteotia, 
. In the
following 
lines the network of roads is described. In each of
these lines there are two integers 
and 
(
; 
), meaning that the towns
and 
are connected by a road. In the line
there is one integer 
equal to the number of towns
Byteasar should visit, 
. In the following
lines there are numbers of successive towns on Byteasar's route -
one number per line.
Output
In the first and only line of the standard output there should be one integer equal to the total time of Byteasar's trip.
Example
For the input data:
5 1 2 1 5 3 5 4 5 4 1 3 2 5
the correct result is:
7
Task author: Tomasz Walen.