number Incorrect of edges

Hi, I'm trying metis but I've a problem.
I'm running metis with this input file:

%METIS INPUT FILE
8 7 1
2 1
3 1
4 1
5 1
6 1
7 1
8 1

I need to partition this graph into two parts, but when I run: pmetis inputfile.txt 2, metis says:


In the first line of the file, you specified that the graph contained
7 edges. However, I only found 3 edges in the file.
Please specify the correct number of edges in the first line of the file.

As you can see, this is not OK, because my file have 7 edges. What is te problem? I'm doing wrong?
Thanks

RE: It appears that the input

It appears that the input graph is directed. Metis requires the graph to be undirected; that is both (u,v) and (v,u) edges should be there.
Also, the #of edges in the first line should be the number of undirected edges; i.e., (u,v) and (v,u) should only contribute 1 to the # of edges count.