Forethought Future Cup - Final Round (Onsite Finalists Only)
B
Chladni Figure
Codeforces
1900
原题
← AC →
翻译中…

Inaka has a disc, the circumference of which is $n$ units. The circumference is equally divided by $n$ points numbered clockwise from $1$ to $n$, such that points $i$ and $i + 1$ ($1 \leq i \lt n$) are adjacent, and so are points $n$ and $1$.

翻译中…

There are $m$ straight segments on the disc, the endpoints of which are all among the aforementioned $n$ points.

翻译中…

Inaka wants to know if her image is rotationally symmetrical, i.e. if there is an integer $k$ ($1 \leq k \lt n$), such that if all segments are rotated clockwise around the center of the circle by $k$ units, the new image will be the same as the original one.

翻译中…

Input

翻译中…

The first line contains two space-separated integers $n$ and $m$ ($2 \leq n \leq 100\,000$, $1 \leq m \leq 200\,000$) — the number of points and the number of segments, respectively.

翻译中…

The $i$-th of the following $m$ lines contains two space-separated integers $a_i$ and $b_i$ ($1 \leq a_i, b_i \leq n$, $a_i \neq b_i$) that describe a segment connecting points $a_i$ and $b_i$.

翻译中…

It is guaranteed that no segments coincide.

翻译中…

Output

翻译中…

Output one line — "Yes" if the image is rotationally symmetrical, and "No" otherwise (both excluding quotation marks).

翻译中…

You can output each letter in any case (upper or lower).

翻译中…

Note

翻译中…

The first two examples are illustrated below. Both images become the same as their respective original ones after a clockwise rotation of $120$ degrees around the center.

翻译中…

image

翻译中…

样例

Input #1
12 6
1 3
3 7
5 7
7 11
9 11
11 3
Output #1
Yes
InputCopy OutputCopy
Input #2
9 6
4 5
5 6
7 8
8 9
1 2
2 3
Output #2
Yes
InputCopy OutputCopy
Input #3
10 3
1 2
3 2
7 2
Output #3
No
InputCopy OutputCopy
Input #4
10 2
1 6
2 7
Output #4
Yes
InputCopy OutputCopy
题目信息
题号
1147B
时间限制
3 s
内存限制
256 MB
标签
暴力
字符串

题面与样例版权归 Codeforces 及出题人所有;中文翻译由 AI 生成(CI 管线),如有出入请以原文为准。