Graph Nodes:
X3;X7;X5;X10;X12;X9;X4;X13;X1;X8

Graph Edges:
1. X3 <-> X12
2. X3 o-> X4
3. X3 <-> X13
4. X3 <-> X1
5. X7 o-> X10
6. X7 <-> X4
7. X7 <-> X1
8. X7 <-> X8
9. X5 o-> X8
10. X10 <-> X12
11. X9 o-> X12
12. X13 <-> X8
13. X1 --> X8
