Model: Example1
R1: 	 ==> 1 A 
R2: 	1 A  ==> 1 B +1 E 
R3: 	2 B  ==> 1 D 
R4: 	1 A  <==> 1 C 
R5: 	1 C  ==> 1 D 
R6: 	1 C  <==> 1 D 
R7: 	1 D  ==> 
R8: 	1 E  ==>