1998 Northeast U.S. Regional Programming Contest

Problem 4: We Ship Cheap

jumpship.cc

The JumpShip package shipping company is always interested in reducing their costs. JumpShip delivers packages among a number of cities by tying them to the landing gear of unsuspecting FedEx and UPS aircraft. Because of pesky security issues, JumpShip does not guarantee that they will be able to get a package from city A to city B in a single trip; often, they must send a package through intermediate points where fewer people are watching... .

In any case, JumpShip "borrows" the weekly security schedules from FedEx and UPS each Sunday in order to plan efficient routes for its customers' packages in the upcoming week. From the schedule, they determine which routes will be accessible for use. Your task is then to compute how many flights are required for a particular package to be sent from one city to another.

Input

The input file to your program consists of two parts. On the first line there is an integer indicating the number of departure cities available. Then, there are that many lines, each beginning with the airport code of a departure city, followed by the destination airports reachable in a single flight from that departure city (separated by whitespace). After this set of available flights appear queries, one per line. Each query consists of two cities, and the program must compute the number of flights required to get a package from the first to the second city, using only flights available in the original schedule.

Output

The output should consist of one integer for each query -- indicating the number of flights required to get a package from start to finish. If it is not possible to get a package from the first city to the second, you should print the line "Try again next week." instead.

Sample input:

3
LGA JFK LAX ORD
ORD EVV LIM
LIM LAX LGA
LIM EVV
JFK LGA
ORD ORD
LGA LIM

Sample output:

3
Try again next week.
0
2