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

Input

Input starts with the value of n and the n names of the vertices. Then comes the value of m and follow the m arcs, made up by the name of two vertices, without repetitions nor autoloops. Then follows a pair of vertices x,y. You can assume that x and y belong to the graph.

Output

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

Public test cases

**Input**

8 bcn prs mad rom lsb ber lon dub 10 bcn prs prs mad rom lsb rom dub ber lon lsb dub dub lsb mad lon bcn ber ber bcn bcn mad

**Output**

yes

**Input**

8 bcn prs mad rom lsb ber lon dub 10 bcn prs prs mad rom lsb rom dub ber lon lsb dub dub lsb mad lon bcn ber ber bcn rom bcn

**Output**

no

Information

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