#!/usr/bin/env python
# coding=utf-8

"""491. Double pandigital number divisible by 11
https://projecteuler.net/problem=491

We call a positive integer _double pandigital_ if it uses all the digits 0 to
9 exactly twice (with no leading zero). For example, 40561817703823564929 is
one such number.

How many double pandigital numbers are divisible by 11?
"""
