Given an undirected graph, determine whether it is bi-colorable or not. A graph is called bi-colorable if only two colors are used and each node is assigned a color such that all adjacent nodes have different assigned colors. Note that all nodes are connected.
The input consists of several test cases. Each test case starts with a line containing a number N which represents N nodes indexed from 1 to N.( 0 < N < 1000) The second line contains a number K. After this, there are K lines, each containing two numbers that indicate two end nodes of an edge. When N is equal to 0, the input ends.
If the graph is bi-colorable, print “BICOLORABLE”. Otherwise, print “NOT BICOLORABLE”.