ma
 0 !
 * 1 2
1  a
*  2 1
2 ! 
* 0  1
	* 1 2
*	 3 4
* 	4 8

3 a
* 2	 0.5
* 3 	0.5
4 a
* 3 1	
4 b

*	1 0.5 
* 5	0.5	
5 a
* 5 1