Reading in a dataset with uneven variable lengths

Suppose I have a text file that I want to read into R like the
following:

X	Y
649	699
657	891
714	632
849	727
721	597
791	868
874	652
405	978
	733
	549
	790

This is a simple example -- I could have a huge file with many
columns of unequal lengths.

What is the best way to do it?  I can't see how a data frame
can be used.  I checked the FAQ and did a web search on the topic
but I came up empty.

Jason