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)

#方針: 753数を全列挙
n = gets.to_i

list = ["7","5","3"]
ary = []

def is_753?(s)
  f7=f5=f3 = false
  s.chars do |c|
    case c
    when "7"
      f7=true
    when "5"
      f5=true
    when "3"
      f3=true
    end
  end
  return f7&&f5&&f3
end

ary = (3..9).inject([]){|memo, digit| memo + ["7","5","3"].repeated_permutation(digit).select{|a| is_753?(a.join)}.map(&:join)}

ans = 0
ary.each_with_index do |a, i|
  if a.to_i <= n
    ans+=1
  end
end
 
p ans