2286：God and Devil

There are many gods and devils living on HDU Island, and echo is one of them. Gods always tell the truth whereas devils sometimes tell the truth but sometimes not. What's more, every god and devil knows all the others are a god or a devil.
One day, an accident unfortunately happened which made echo lose her memory. She was so despairing and determined to turn to others for help. She asked all the residents a question, but all of the answers were merely "Be careful! X is a devil!". As a result she failed to arouse her memory. However, she has to find out a method to calculate the minimum number of devils on the island. Could you help echo to manage it well?

There are multi-cases (The total number of cases won't exceed 20). First line is an integer N(1<=N<=15000), the total number of gods and devils. Then N lines follow, each line includes a name, and the length of each name won't exceed 30. The first name is "echo". The next N-1 lines will be as the formation "A says: Be careful! B is a devil!"(A is different from B), and you can assume that at least one of them will consider echo is a devil and says "Be careful! echo is a devil!".

Output the minimum number of devils in the island.