Sequoia outputs invalid edge IDs

Question about Sequoia.

Given the input
```
./src/sequoia -e MaxCardSet -f formulas/longest-cycle.mso -g ../../easy_graphml/contiki_dhcpc_dhcpc_init.graphml -2
```
Sequoia outputs
size: 8, members: 64, 63, 29, 27, 28, 61, 62, 30

But there is no node or edge with id 64. But the nodes 27,28,29,30 indeed form a cycle. So what does that mean?