Bicolouring
----------
The four-colour theorem states that every planar map can be coloured
using only four colours in such a way that no region is coloured using
the same colour as a neighbour.  After being open for over 100 years, the
theorem was proven in 1976 with the assistance of a computer.

Here you are asked to solve a simpler problem.  Decide whether a given
connected graph can be bicoloured, i.e., can the nodes be painted
red and black such that no two adjacent nodes have the same
colour.

To simplify the problem, you can assume the graph will be connected,
undirected, and not contain self-loops (i.e., edges from a node to
itself).

Input
-----
The input consists of several test cases.  Each test case starts with a
line containing two integers n and m, where 0 < n < 1000.
These numbers represent the number of nodes and the number of edges
in the input graph.  Each node is labeled by a number from 1 to n.
After this, m lines follow, each containing two node numbers
specifying an edge.

An input with n = m = 0 marks the end of the input and is not to be processed.

Output
------
Decide whether the input graph can be bicoloured, and print the result
as shown below. 

Sample Input
------------
3 3
1 2
2 3
3 1
9 8
1 2
1 3
1 4
1 5
1 6
1 7
1 8
1 9
0 0

Sample Output
-------------
NOT BICOLOURABLE.
BICOLOURABLE.