def merge(filehandle_1, filehandle_2, output_filehandle):
    line2 = filehandle_2.readline()
    for line1 in filehandle_1.readlines():
        while line2 != '' and line2 <= line1:
            output_filehandle.write(line2)
            line2 = filehandle_2.readline()
        output_filehandle.write(line1)
    while line2 != '':
        output_filehandle.write(line2)
        line2 = filehandle_2.readline()