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: Wrong Answer)

a=gets.chomp.to_i
if a < 357
  puts 0
else
  l = a.to_s.length - 3
  c_ary = [[3,5,7]]
  d_ary = [3, 5, 7]
  l.times do |i|
    i += 1
    [3,5,7].repeated_permutation(i){ |n| c_ary << (d_ary + n) }
  end
  n_ary = []
c_ary.each do |c|
  n_ary << c.permutation.map { |n| n.join.to_i}
end
n_ary = n_ary.flatten.uniq
ans_ary = n_ary.select { |n| n < a }
puts ans_ary.size
end