4 Cycle

Given a simple undirected graph, check if there is a 4-cycle or not. A 4-cycle is a sequence of 4 distinct nodes a1, a2, a3, a4 such that there is an edge between a1 and a2, a2 and a3, a3 and a4, a4and a1. Input The first line contains N, M denoting the number of nodes and edges in the graph. The following M lines contain 2 integers u, v denoting an undirected edge between u and v. It is guara