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#                                #
# Last modified 2025/06/23       # 
#                                #
# Georgi Marinov                 #
#                                # 
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import sys
import os

def run():

    if len(sys.argv) < 3:
        print 'usage: python %s inputfilename ratio_factor outfileprefix [-noheader]' % sys.argv[0]
        print '\tnote: use - instead of an input filename to indicate standard input' 
        print '\tnote: the ratio factor is meant to be as R:1, i.e. 1 for 1:1, 2 for 2:1, etc.' 
        sys.exit(1)

    inputfilename = sys.argv[1]
    R = int(sys.argv[2]) + 1
    outfileprefix = sys.argv[3]

    doHeader = True
    if '-noheader' in sys.argv:
        doHeader = False

    doStdInput = False
    if inputfilename == '-':
        doStdInput = True

    outfile1 = open(outfileprefix + 'main','w')
    outfile2 = open(outfileprefix + 'secondary','w')

    if doStdInput:
        input_stream = sys.stdin
    else:
        input_stream = open(inputfilename)
    i=0
    for line in input_stream:
        if line.startswith('#'):
            if doHeader:
                outfile2.write(line)
                outfile1.write(line)
            continue
        i+=1
        if i % R == 0:
            outfile2.write(line)
        else:
            outfile1.write(line)
        
    outfile1.close()
    outfile2.close()

run()