Print the position string equivalent of a positive integer. Examples:

        0: zeroeth
        1: first
        2: second
        14: 14th
        21: 21st

def positional_number_string(n):
    """Print the position string equivalent of a positive integer. Examples:

        0: zeroeth
        1: first
        2: second
        14: 14th
        21: 21st
    """
    if n > 20:
        suffix = positional_suffix[n % 10]
        return "%d%s" % (n, suffix)
    elif n > 3:
        return "%dth" % n
    elif n == 3:
        return "third"
    elif n == 2:
        return "second"
    elif n == 1:
        return "first"
    return "zeroeth"