Problem:
Score : 300 points

Problem Statement

You are given an integer N. Among the integers between 1 and N (inclusive), how many Shichi-Go-San numbers (literally "Seven-Five-Three numbers") are there?

Here, a Shichi-Go-San number is a positive integer that satisfies the following condition:

When the number is written in base ten, each of the digits 7, 5 and 3 appears at least once, and the other digits never appear.

Constraints

1 \leq N < 10^9

N is an integer.

Input

Input is given from Standard Input in the following format:

N

Output

Print the number of the Shichi-Go-San numbers between 1 and N (inclusive).

Sample Input 1

575

Sample Output 1

4

There are four Shichi-Go-San numbers not greater than 575: 357, 375, 537 and 573.

Sample Input 2

3600

Sample Output 2

13

There are 13 Shichi-Go-San numbers not greater than 3600: the above four numbers, 735, 753, 3357, 3375, 3537, 3557, 3573, 3575 and 3577.

Sample Input 3

999999999

Sample Output 3

26484

Solution in Ruby (2.3.3) (judge verdict: Accepted)

#!/usr/bin/env ruby
n = STDIN.readline.strip.to_i

def make_753()
  p = []
  for i in 1..9 do
    p += _make_753(i)
  end
  p
end

def _make_753(d)
  p = ['7', '5', '3']
  for i in 2..d
    p = p.product(['7', '5', '3']).map{|d| d.join}.flatten
  end
  p.select{|s| exist_753(s)}.map(&:to_i)
end

def exist_d(d, s)
  s.split('').include?(d.to_s)
end

def exist_753(s)
  exist_d(7, s) and exist_d(5, s) and exist_d(3, s)
end

_753 = make_753()
puts _753.count{|d| n >= d}