param n := 11;
set A := (1,2) (1,3) (2,3) (2,4) (3,5) (3,6) (4,6) (4,7) 
(5,6) (5,9) (6,8) (6,9) (7,8) (7,10) (8,9) (8,10) (9,11) (10,11);
param costo :=
1	2	2.5
1	3	3
2	3	1.7
2	4	2.5
3	5	1.7
3	6	2.8
4	6	2
4	7	1.5
5	6	2
5	9	5
6	8	3
6	9	4.7
7	8	1.5
7	10	2.3
8	9	2
8	10	1.1
9	11	3.3
10	11	2.7;
param origine := 1; param destinazione := 11;