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.

No tag edit access

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

×
B. Pairs

time limit per test

2 secondsmemory limit per test

256 megabytesinput

standard inputoutput

standard outputToad Ivan has $$$m$$$ pairs of integers, each integer is between $$$1$$$ and $$$n$$$, inclusive. The pairs are $$$(a_1, b_1), (a_2, b_2), \ldots, (a_m, b_m)$$$.

He asks you to check if there exist two integers $$$x$$$ and $$$y$$$ ($$$1 \leq x < y \leq n$$$) such that in each given pair at least one integer is equal to $$$x$$$ or $$$y$$$.

Input

The first line contains two space-separated integers $$$n$$$ and $$$m$$$ ($$$2 \leq n \leq 300\,000$$$, $$$1 \leq m \leq 300\,000$$$) — the upper bound on the values of integers in the pairs, and the number of given pairs.

The next $$$m$$$ lines contain two integers each, the $$$i$$$-th of them contains two space-separated integers $$$a_i$$$ and $$$b_i$$$ ($$$1 \leq a_i, b_i \leq n, a_i \neq b_i$$$) — the integers in the $$$i$$$-th pair.

Output

Output "YES" if there exist two integers $$$x$$$ and $$$y$$$ ($$$1 \leq x < y \leq n$$$) such that in each given pair at least one integer is equal to $$$x$$$ or $$$y$$$. Otherwise, print "NO". You can print each letter in any case (upper or lower).

Examples

Input

4 6 1 2 1 3 1 4 2 3 2 4 3 4

Output

NO

Input

5 4 1 2 2 3 3 4 4 5

Output

YES

Input

300000 5 1 2 1 2 1 2 1 2 1 2

Output

YES

Note

In the first example, you can't choose any $$$x$$$, $$$y$$$ because for each such pair you can find a given pair where both numbers are different from chosen integers.

In the second example, you can choose $$$x=2$$$ and $$$y=4$$$.

In the third example, you can choose $$$x=1$$$ and $$$y=2$$$.

Codeforces (c) Copyright 2010-2021 Mike Mirzayanov

The only programming contests Web 2.0 platform

Server time: Jul/29/2021 21:51:23 (g1).

Desktop version, switch to mobile version.

Supported by

User lists

Name |
---|