As you probably know the children of rich people are the worst.Take John for example
the son of the boss of a big company in Europe.One Week-end he started to get bored and
his father proposed him to go to Asia and visit some rice lands.

Problem:

Jonh decided to accept the offert, but with to conditions:a)to see all the rice lands ;
b)not to see the same land twice or else he will get really mad...
In Asia there are N towns Some of the towns are connected directly by one,two or more roads.
A rice land is cut by exactly one road,a road cuts exactly one rice land.
The roads are bidirectional.
So, the trip begins.The father takes his son to an arbitrary town with his personal helicopter.Then he leaves while John
starts visiting the lands (The lenghts of the roads are very small so he can walk:)
After a while, he realises that there are some lands which he didn't visit but he cannot move
from the town he is in without visiting a land he already visited.What to do?
He calls his father.The father has no choice.He comes with the helicopter and takes him to another town.
Finally the task.Which is the minimum number of helicopter rides in order for Jonh to see all the lands?
The towns are labeled 1 to N and there are no isolated towns.

Input data:

The first line of the input file contains N and M the number of towns and the number of roads
The next M Lines contains two integers xi,yi xi!=yi the two towns which are connected by the i-th road

Output data:

The only line of the output file should contain P the number of rides.