英语翻译

英语翻译
Your task is so easy.I will give you an undirected graph,and you just need to tell me whether the graph is just a circle.A cycle is three or more nodes V1,V2,V3,...Vk,such that there are edges between V1 and V2,V2 and V3,...Vk and V1,with no other extra edges.The graph will not contain self-loop.Furthermore,there is at most one edge between two nodes.
Input
There are multiple cases (no more than 10).
The first line contains two integers n and m,which indicate the number of nodes and the number of edges (1