Zero loves palying Sanguo game very much, The battle of Red Cliff is one of scenes. Now he will put a fire to one of ships. Some ships are connected, some are not.Now, zero puts his fire, please tell him how many ships will be left.

Input until EOF.
There are two positive integers N(2<N<100) and M(0<M<100), N means the number of ships, M means the number of command.
Then M lines follows. Each line has two positive integers x and y means he will connect these two ships by a rope.
Last line will include a number of ship's that zero will burn.

The ship's number is from 1 N, every ship which is connected a burning ship will also be burned.Now, please tell zero how many ships will be left.