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.
3 4 10 20 30 40 50 60
70 80 2 1 3 2 200 3 10 100 20 80 30 50