The "Hamilton cycle problem" is to find a simple cycle that contains every vertex in a graph. Such a cycle is called a "Hamiltonian cycle".
In this problem, you are supposed to tell if a given cycle is a Hamiltonian cycle.
Each input file contains one test case. For each case, the first line contains 2 positive integers N (2
n V1 V2 ... Vn
where n is the number of vertices in the list, and Vi's are the vertices on a path.
For each query, print in a line YES