<｜begin▁of▁sentence｜>### Instruction:
Given a graph with edge set [(0, 1), (1, 2), (2, 3), (3, 4), (4, 5)], can you calculate the path length histogram using igraph and determine the number of unconnected vertex pairs?
### Response:
import igraph as ig

# Create a graph
g = ig.Graph(edges=[(0, 1), (1, 2), (2, 3), (3, 4), (4, 5)])

# Calculate the path length histogram for the graph
histogram = g.path_length_hist()
print(histogram)

# Print the number of unconnected vertex pairs
print('Unconnected pairs:', histogram.unconnected)
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