<｜begin▁of▁sentence｜>### Instruction:
Given a graph with edges [(1, 2), (1, 3), (3, 4), (2, 5)], for vertex 1, what is the size of the neighborhood that is reachable within at most 2 steps?
### Response:
import networkx as nx

# Create a graph
G = nx.Graph()
G.add_edges_from([(1, 2), (1, 3), (3, 4), (2, 5)])

# Define vertex or vertices and order
vertex = 1  # For a single vertex
order = 2  # Maximum number of steps

# Use NetworkX's single_source_shortest_path_length to find the neighborhood size
neighborhood_size = len(nx.single_source_shortest_path_length(G, vertex, cutoff=order)) - 1

print(f'Neighborhood size of vertex {vertex}: {neighborhood_size}')
<|EOT|>
