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)

def is_753?(x)
  s = x.to_s(4)
  s.include?('1') && s.include?('2') && s.include?('3') && !s.include?('0')
end

def henkan(n)
  n.to_s(4).tr('3', '7').tr('2', '5').tr('1', '3').to_i
end

def main(n)
  digits = n.size
  cnt = 0
  (4**(digits + 1)).times do |i|
    return cnt if henkan(i) > n
    cnt += 1 if is_753?(i)
  end
  cnt
end

n = gets.to_i
puts main(n)