dgleich

import collections
import sys

# setup the graph
G = {
  1:set([ 2, 3, 5, 6,]),
  2:set([ 1, 4,]),
  3:set([ 1, 6, 7,]),
  4:set([ 2, 5, 7, 8,]),
  5:set([ 1, 4, 6, 8, 9, 10,]),