A company has a network of ~N~ servers, numbered ~1~ to ~N~. These servers are linked through two-way direct ~M~ connections, ensuring seamless communication across the network. The stability of these connections is vital for the company's. The connections are bidirectional - this means if server ~A~ can directly communicate with server ~B~, then server ~B~ can also directly communicate with server ~A~.

A critical connection is a link between two servers where, if this connection fails or becomes unavailable, the network becomes disconnected. This means that there will be at least two servers that can no longer communicate with each other, either directly or through other servers.

Your task is to identify whether there are critical connections in the network.

Input

• The first line contains two integers ~N~ ~(1 \le N \le 100)~ and ~M~ ~(1 \le M \le 5000)~ - the number of servers and connections, respectively.
• The next ~M~ lines describe the connections. Each line contains two integers ~u, v~ ~(1 \le u, v \le N)~ - representing a direct connection between server ~u~ and server ~v~.

Output

• Print YES if there exists at least one if at least one critical connection exists, otherwise print NO.

Sample

Sample Input 1

5 5
1 2
2 4
4 1
2 3
4 5

Sample Output 1

YES

Notes

In the sample testcase,

The figure above represents a network with ~5~ severs (nodes) and ~5~ connections (edges).

• If the connection between location ~4~ and ~5~ is removed, The network becomes disconnected.
• Similarly, removing the connection between ~2~ and ~3~. Therefore, the answer is YES.