Tunnel

Mirko stands at the entrance of a tunnel and Slavko stands at the exit. Each of them writes down the licence plate of every car in the order the cars drive past, and sends the list to a police patrol a few kilometres down the road.

From the two lists the patrol can decide without any doubt that certain drivers overtook inside the tunnel, which is strictly forbidden.

Write a program that counts the drivers who can be proven to have overtaken.

Assume the traffic inside the tunnel behaved normally, with no collisions and no cars stopping.

The first line contains the number of cars $N$ ($1 \le N \le 1000$).

The next $N$ lines contain the licence plates in the order the cars entered the tunnel, one plate per line.

The next $N$ lines contain the licence plates of the same cars in the order they left the tunnel, one plate per line.

A licence plate is 6 to 8 characters long and uses only the uppercase English letters A to Z and the digits 0 to 9. The $N$ plates are all different.

Print the number of drivers the police can certainly punish for illegal overtaking.