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Write a program that, given an undirected graph, tells if we can paint all vertices with only two colors, in such a way that no two neighboring vertices have the same color.

Input

Input consists of several cases,
each with the number of vertices n and the number of edges m,
followed by m pairs x y indicating an edge between x and y.
Suppose 1 ≤ n ≤ 10^{4},
0 ≤ m ≤ 5n,
that vertices are numbered from 0 to n − 1,
x ≠ y,
and that there is no more than one edge between any pair x y.

Output

For every case, print “yes” if the graph is two-colorable, and “no” otherwise.

Public test cases

**Input**

2 1 0 1 4 3 1 2 3 2 3 1 1 0 4 2 0 3 2 1

**Output**

yes no yes yes

Information

- Author
- Salvador Roura
- Language
- English
- Translator
- Salvador Roura
- Original language
- Catalan
- Other languages
- Catalan
- Official solutions
- C++ Python
- User solutions
- C++ Python