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 (2.7.1) (judge verdict: Accepted)

require "set"
n = gets.chomp.to_i

# 3進数を利用して七五三数を直接集める
hash = {"0"=>"3", "1"=>"5", "2"=>"7"}
arr = []
# 桁数だけ回す
(3..9).each do |digit|
  (3**digit).times do |i|
    set = Set.new
    num = ""
    ("%0#{digit}d" % i.to_s(3)).each_char do |c|
      num += hash[c]
      set << hash[c]
    end
    # 3,5,7が1回以上表れた場合に挿入
    arr << num.to_i if set.length == 3
  end
end

# 番兵
arr << 10 ** 9
# arrは作り方からsort済なのでindexを求めれば良い
puts arr.index{|a| a > n}