Given an undirected graph with m vertices and m arcs, we wish to know if there is a directed path between two given vertices.

Input

Input starts with n i m. Then follow m pairs u,v, with u ≠ v, indicating an arc from u to v. We have that 0≤ u<n and 0≤ v<n and there are no repeated arcs. Then follows, a pair x,y with 0≤ x<n and 0≤ y <n.

Output

Write “yes” o “no” according to whether there is or not a path from x to y.

Public test cases

**Input**

8 10 1 4 4 6 7 2 7 5 0 3 2 5 5 2 6 3 1 0 0 1 1 3

**Output**

yes

**Input**

8 10 1 4 4 6 7 2 7 5 0 3 2 5 5 2 6 3 1 0 0 1 7 6

**Output**

no

Information

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