[igraph] Problem with dimacs file

[Raphael Clifford]

I am trying to read

http://www.dis.uniroma1.it/challenge9/data/USA-road-d/USA-road-d.NY.gr.gz

in python. I have unzipped it and then I run

#!/usr/bin/python
fname = "NY.gr"
from igraph import *
g = Graph.Read_DIMACS(fname)


This gives me

Traceback (most recent call last):
  File "./ashleyconcert.py", line 4, in <module>
    g = Graph.Read_DIMACS(fname)
  File "/usr/lib/python2.7/dist-packages/igraph/__init__.py", line
1624, in Read_DIMACS
    graph, source, target, cap = super(Graph, cls).Read_DIMACS(f, directed)
igraph._igraph.InternalError: Error at foreign.c:820: 'a' lines are
allowed only in MAX problem files, Parse error

What is igraph expecting as input?

Raphael