##################################
#                                #
# Last modified 11/23/2009       # 
#                                #
# Georgi Marinov                 #
#                                # 
##################################

import sys

try:
	import psyco
	psyco.full()
except:
	pass

def run():

    if len(sys.argv) < 2:
        print 'usage: python %s inputfilename outfilename' % sys.argv[0]
        sys.exit(1)

    inputfilename = sys.argv[1]
    outputfilename = sys.argv[2]

    listoflines = open(inputfilename)
    lineslist = listoflines.readlines()
    outfile = open(outputfilename, 'w')
    if lineslist[0][0:5]=='track':
        outfile.write(lineslist[0])
    for line in lineslist:
        if line[0:3] == 'chr':
            outfile.write(line)
    outfile.close()

run()