Graph Nodes:
X1;X2;X3;X4;X5;X6;X7;X8;X9;X10;X11;X12;X13;X14;X15;X16;X17;X18;X19;X20

Graph Edges:
1. X1 --> X19
2. X1 --- X2
3. X1 --- X6
4. X1 --- X9
5. X10 --> X13
6. X11 --> X12
7. X11 --> X14
8. X11 --> X18
9. X14 --> X18
10. X18 --> X20
11. X19 --> X20
12. X2 --> X10
13. X20 --> X13
14. X3 --> X11
15. X3 --> X14
16. X3 --- X4
17. X3 --- X8
18. X4 --> X19
19. X5 --> X12
20. X5 --> X13
21. X5 --> X16
22. X5 --> X20
23. X6 --> X10
24. X7 --> X12
25. X7 --> X18
26. X8 --> X16
27. X8 --- X17
28. X9 --> X11
29. X9 --- X15
30. X9 --> X16

