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

"""71. Ordered fractions
https://projecteuler.net/problem=71

Consider the fraction, _n/d_ , where _n_ and _d_ are positive integers. If _n_
< _d_ and HCF( _n,d_ )=1, it is called a reduced proper fraction.

If we list the set of reduced proper fractions for _d_ ≤ 8 in ascending order
of size, we get:

1/8, 1/7, 1/6, 1/5, 1/4, 2/7, 1/3, 3/8, **2/5** , 3/7, 1/2, 4/7, 3/5, 5/8,
2/3, 5/7, 3/4, 4/5, 5/6, 6/7, 7/8

It can be seen that 2/5 is the fraction immediately to the left of 3/7.

By listing the set of reduced proper fractions for _d_ ≤ 1,000,000 in
ascending order of size, find the numerator of the fraction immediately to the
left of 3/7.
"""
