071.py

#!/usr/bin/python
# -*- coding: utf-8 -*-

#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.

#Answer:
	#428570

from time import time; t=time()

M=1000000

x = M//7*7+5
if x > M: x -= 7
print((3*x-1)//7)#, time()-t