set V := 1 2 3 4 5;
set E := (1,2) (1,3) (2,3) (2,4) (2,5) (3,5) (4,5);

param c :=
1 2   3 
1 3   2
2 3   4
2 4   6
2 5   5
3 5   1
4 5   7;