text: #!/usr/bin/env python
  import ABPUtils
  import sys
  import networkx as nx
  g = ABPUtils.ReadGraph(sys.argv[1])
  r = []
  for e in g.edges():
  	if g[e[0]][e[1]]['cost'] < 0:
  		r.append(e)
  
  g.remove_edges_from(r)
  ABPUtils.WriteGraph(g, sys.argv[2])
   
  