About the input file format

[Xin Zhang]

I try to test in a directed graph representing web of six pages. My input file look like this:
1,2
1,3
3,1
3,2
3,5
4,5
4,6
5,4
5,6
6,4

When I use such command: $ ./pagerank -a 0.9 -d ',' graph.txt
I get strange output as follows:
Reading input from graph.txt...
read 10 lines, 11 vertices
Calculating pagerank...
Done calculating!
1 = 0.0613121275052437
= 0.107296025531954
= 0.0889024663212696
3 = 0.0613121275052437
= 0.0797056867159276
= 0.132127630172984
4 = 0.116492805137295
= 0.141324409778326
5 = 0.0613121275052437
= 0.0889024663212696
6 = 0.0613121275052437
s = 1

Why 11 vertices……I am confused. I know it must be my fault, could you please point it out?Many thanks.