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

l = N.to_s.length
n = ['3','5','7']
m = ['3','5','7']
2.upto(l) do |i|
    tmp = []
    m.each do |j|
        n.each do |k|
            if k.length == i-1
                tmp << k + j
            end
        end
    end
    n += tmp
end

ans = 0
n.each do |v|
    if v.include?('3') && v.include?('5') && v.include?('7')
        if v.to_i <= N
            ans += 1
        end
    end
end
puts ans