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)

n = gets.to_i
a = [[3,5,7]]

8.times do |i|
  x = []
  d = a[i].dup
  [3,5,7].each do |j|
    v = j * (10 ** (i+1))
    d.each do |t|
      x << (t + v)
    end
  end
  a << x
end
a.flatten!
ans = 0
a.each do |v|
  str = v.to_s
  check = [false,false,false]
  str.each_char {|c|
    if c == "3"
      check[0] = true
    elsif c == "5"
      check[1] = true
    elsif c == "7"
      check[2] = true
    end
  }
  ans += 1 if  v <= n && check[0] && check[1] && check[2]
end
p ans