Virtual contest is a way to take part in past contest, as close as possible to participation on time. It is supported only ICPC mode for virtual contests.
If you've seen these problems, a virtual contest is not for you - solve these problems in the archive.
If you just want to solve some problem from a contest, a virtual contest is not for you - solve this problem in the archive.
Never use someone else's code, read the tutorials or communicate with other person during a virtual contest.

dfs and similar

graphs

trees

*2100

No tag edit access

The problem statement has recently been changed. View the changes.

×
E. We Need More Bosses

time limit per test

2 secondsmemory limit per test

256 megabytesinput

standard inputoutput

standard outputYour friend is developing a computer game. He has already decided how the game world should look like — it should consist of $$$n$$$ locations connected by $$$m$$$ two-way passages. The passages are designed in such a way that it should be possible to get from any location to any other location.

Of course, some passages should be guarded by the monsters (if you just can go everywhere without any difficulties, then it's not fun, right?). Some crucial passages will be guarded by really fearsome monsters, requiring the hero to prepare for battle and designing his own tactics of defeating them (commonly these kinds of monsters are called bosses). And your friend wants you to help him place these bosses.

The game will start in location $$$s$$$ and end in location $$$t$$$, but these locations are not chosen yet. After choosing these locations, your friend will place a boss in each passage such that it is impossible to get from $$$s$$$ to $$$t$$$ without using this passage. Your friend wants to place as much bosses as possible (because more challenges means more fun, right?), so he asks you to help him determine the maximum possible number of bosses, considering that any location can be chosen as $$$s$$$ or as $$$t$$$.

Input

The first line contains two integers $$$n$$$ and $$$m$$$ ($$$2 \le n \le 3 \cdot 10^5$$$, $$$n - 1 \le m \le 3 \cdot 10^5$$$) — the number of locations and passages, respectively.

Then $$$m$$$ lines follow, each containing two integers $$$x$$$ and $$$y$$$ ($$$1 \le x, y \le n$$$, $$$x \ne y$$$) describing the endpoints of one of the passages.

It is guaranteed that there is no pair of locations directly connected by two or more passages, and that any location is reachable from any other location.

Output

Print one integer — the maximum number of bosses your friend can place, considering all possible choices for $$$s$$$ and $$$t$$$.

Examples

Input

5 5

1 2

2 3

3 1

4 1

5 2

Output

2

Input

4 3

1 2

4 3

3 2

Output

3

Codeforces (c) Copyright 2010-2023 Mike Mirzayanov

The only programming contests Web 2.0 platform

Server time: Dec/07/2023 05:47:12 (l3).

Desktop version, switch to mobile version.

Supported by

User lists

Name |
---|