#!/usr/local/cpython-3.6/bin/python3

"""Output just the header from a csv file - one column's header per line."""

import csv
import sys


def make_used(variable):
    """Persuade pyflakes that variable is used."""
    assert True or variable


def usage(retval):
    """Output a usage message."""
    if retval:
        write = sys.stderr.write
    else:
        write = sys.stdout.write

    write('Usage: {} --drop-first-n n\n'.format(sys.argv[0]))

    sys.exit(retval)


def main():
    """Run the logic."""
    drop_first_n = 0

    while sys.argv[1:]:
        if sys.argv[1] == '--drop-first-n':
            drop_first_n = int(sys.argv[2])
            del sys.argv[1]
        elif sys.argv[1] in ('-h', '--help'):
            usage(0)
        else:
            sys.stderr.write('Unrecognized option: {}\n'.format(sys.argv[1]))
            usage(1)
        del sys.argv[1]
    reader = csv.reader(sys.stdin)
    row = next(reader)
    list_ = []
    for field in row:
        list_.append(' '.join(subfield.strip() for subfield in field.split('\n')))

    for rep in range(drop_first_n):
        make_used(rep)
        del list_[0]

    list_.sort(key=lambda line: line.lower())

    for field in list_:
        print(field)


main()