instances format:

N	C
1	w	a1	a2	...	ak

...

i	w	a1	a2	...	ak

...

N	w	a1	a2	...	ak


where:
N is the number of items
C is the bin capacity
i is a number identifying the item
w is the item weight
a1, ..., ak are the items which are incompatible with item i
