"""
Returns "st", "nd", "rd", or "th" as appropriate for the given day number.
"""
# Copyright © 2004 Saugus.net, Inc.
# All Rights Reserved.

# This software is subject to the provisions of the Zope Public License,
# Version 2.1 (ZPL). A copy of the ZPL should accompany this distribution.
# THIS SOFTWARE IS PROVIDED "AS IS" AND ANY AND ALL EXPRESS OR IMPLIED
# WARRANTIES ARE DISCLAIMED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
# WARRANTIES OF TITLE, MERCHANTABILITY, AGAINST INFRINGEMENT, AND FITNESS
# FOR A PARTICULAR PURPOSE.

if day%10==1 and day%100!=11:
    suffix="st"
elif day%10==2 and day%100!=12:
    suffix="nd"
elif day%10==3 and day%100!=13:
    suffix="rd"
else:
    suffix="th"
return suffix