|Codeforces Round #584 - Dasha Code Championship - Elimination Round (rated, open for everyone, Div. 1 + Div. 2)|
The legendary Farmer John is throwing a huge party, and animals from all over the world are hanging out at his house. His guests are hungry, so he instructs his cow Bessie to bring out the snacks! Moo!
There are $$$n$$$ snacks flavors, numbered with integers $$$1, 2, \ldots, n$$$. Bessie has $$$n$$$ snacks, one snack of each flavor. Every guest has exactly two favorite flavors. The procedure for eating snacks will go as follows:
Help Bessie to minimize the number of sad guests by lining the guests in an optimal way.
The first line contains integers $$$n$$$ and $$$k$$$ ($$$2 \le n \le 10^5$$$, $$$1 \le k \le 10^5$$$), the number of snacks and the number of guests.
The $$$i$$$-th of the following $$$k$$$ lines contains two integers $$$x_i$$$ and $$$y_i$$$ ($$$1 \le x_i, y_i \le n$$$, $$$x_i \ne y_i$$$), favorite snack flavors of the $$$i$$$-th guest.
Output one integer, the smallest possible number of sad guests.
5 4 1 2 4 3 1 4 3 4
6 5 2 3 2 1 3 4 6 5 4 5
In the first example, Bessie can order the guests like this: $$$3, 1, 2, 4$$$. Guest $$$3$$$ goes first and eats snacks $$$1$$$ and $$$4$$$. Then the guest $$$1$$$ goes and eats the snack $$$2$$$ only, because the snack $$$1$$$ has already been eaten. Similarly, the guest $$$2$$$ goes up and eats the snack $$$3$$$ only. All the snacks are gone, so the guest $$$4$$$ will be sad.
In the second example, one optimal ordering is $$$2, 1, 3, 5, 4$$$. All the guests will be satisfied.