The famous ACM (Advanced Computer Maker) Company has rented a floor of a building whose shape is in the following figure.
The floor has 200 rooms each on
the north side and south side along the corridor. Recently the Company made a
plan to reform its system. The reform includes moving a lot of tables between
rooms. Because the corridor is narrow and all the tables are big, only one table
can pass through the corridor. Some plan is needed to make the moving efficient.
The manager figured out the following plan: Moving a table from a room to
another room can be done within 10 minutes. When moving a table from room i to
room j, the part of the corridor between the front of room i and the front of
room j is used. So, during each 10 minutes, several moving between two rooms not
sharing the same part of the corridor will be done simultaneously. To make it
clear the manager illustrated the possible cases and impossible cases of
simultaneous moving.
For each room, at most one table
will be either moved in or moved out. Now, the manager seeks out a method to
minimize the time to move all the tables. Your job is to write a program to
solve the manager’s problem.
The input consists of T test cases. The number of test
cases ) (T is given in the first line of the input. Each test case begins with a
line containing an integer N , 1<=N<=200 , that represents the number of
tables to move. Each of the following N lines contains two positive integers s
and t, representing that a table is to move from room number s to room number t
(each room number appears at most once in the N lines). From the N+3-rd line,
the remaining test cases are listed in the same manner as above.
The output should contain the minimum time in minutes
to complete the moving, one per line.