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Points: 3
Time limit: 30.0s
Memory limit: 250M

Problem type
Allowed languages
Python

Toad 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 $y=2$.


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