Given a graph with N nodes and M edges, identify its network topology. Return 1 for Bus (linear chain), 2 for Star (one central node), 3 for Ring (circular), or -1 if none match.

To determine a graph's network topology, first check the number of edges (M) relative to nodes (N). A bus topology has M = N-1 and exactly two nodes with degree 1, while all others have degree 2. A star topology also has M = N-1, but one node has degree N-1 and all others have degree 1. A ring topology has M = N, and every node has a degree of 2. If none of these conditions are met, the topology is none of the specified types.