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

keta = N.to_s.length

def build(list,s,n,keta)
  if s.length == keta
    s_n =  s.to_i
    if s_n <= n && s.include?('3') && s.include?('5') && s.include?('7')
      list << s_n
    end
    return
  end
  
  ['3', '5', '7'].each do |ss|
    build(list, s + ss, n, keta)
  end
end


def calc(n)
  3 - 3*(2**n) + 3**n
end

res = 0

(3...keta).each do |i|
  res += calc(i)
end


list = []
build(list, '', N, keta)
res += list.length

p res