How to open a text file in python?

[achini]

I want to open a text document which contain a graph like this type.
8
16
0 5
2 4
2 3
1 2
0 1
3 4
3 5
0 2

8 vertices & 16 edges.

[bvdet]

A text file is opened with built-in function open(). What do you want to do with the data?