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)

S = gets.chomp
x = S.to_i
N = S.length

# nと同じ桁までの七五三数をすべて列挙して、そのあとx以下のものの数を判定することにする

# 2桁ならなし
if N < 3
  puts 0
  exit
end

ans = 0

3.upto(N) do |d|
  # 3や5だけのものもすべて列挙して、3,5,7すべてあるものだけ保存する
  ['3', '5', '7'].repeated_permutation(d) do |arr|

    next unless arr.include?('3')
    next unless arr.include?('5')
    next unless arr.include?('7')
    
    ans += 1 if arr.join.to_i <= x
  end
end

p ans