<｜begin▁of▁sentence｜>### Instruction:
As a computational biologist, suppose we have obtained a biological network from a GML file, representing interactions between proteins. Using the vcount function in the igraph Python library, we need to count the number of proteins (vertices) in the network. This information is crucial for further analysis and understanding of the network's complexity.
### Response:
from igraph import Graph

# Load your graph; for example, reading from a GML file
graph = Graph.Read_GML('your_graph.gml')

# Use the vcount function to count the vertices in the graph
number_of_vertices = graph.vcount()

# Print the number of vertices
print('Number of vertices in the graph:', number_of_vertices)
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