Problem B - How many knights
----------------------------

The knight is a piece used in chess, a game played on a board with
squares arranged in rows and columns. A knight attacks pieces that are
either (a) two rows and one column away from its position, or (b) one
row and two columns away from its position. The following diagram
illustrates this. The square marked N represents the position of the
knight, and the squares marked X indicate the squares that are under
attack.

	X		X
X				X
		N
X				X
	X		X

In this problem you are to determine the largest number of knights that can
be placed on a board with M rows and N columns so that no
knight is attacking any other. M and N will each be no larger
than 500.

Input
-----

The input consists of pairs of integers giving values for M and N 
(M,N >= 1), followed by a pair of zeroes. The zeroes should not be
processed.

Output
------

For each input pair, display the number of rows
and columns in the board, and the number of knights that can be appropriately
placed, as in the sample shown below.

Sample Input
------------

2 3
5 5
4 7
0 0

Output for Sample Input
-----------------------
				
4 knights may be placed on a 2 row 3 column board.
13 knights may be placed on a 5 row 5 column board.
14 knights may be placed on a 4 row 7 column board.