I wrote a program about this problem and passed it today.
   But in fact,my program can't pass this data:
   4 4
   1 2
   2 1
   3 4
   4 3

   Here is my answer:
   1
   3 4 3 0 0 0
   It is not correct obviously.
   Please add this kind of data.
   At last,sorry for my poor English.

It seems that there is only one connected-graph.
...And no repetitive edges.

Edited by author 01.03.2009 12:27