set NODES := 1 2 3 4;

set ARCS  := (1,2) (1,3) (2,3) (2,4) (3,4);
             

param b :=
1 5
2 -2
3 0
4 -3;


#	cost	lower	upper bound
param: 	c 	l 	u :=
1 2	3	2	5
1 3	2	0	2
2 3	1	0	2
2 4	4	1	3
3 4	4	0	3;