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 (2.7.1) (judge verdict: Accepted)

n = gets.chomp
s = n.size
count = 0
st = 3
while true
    if n.to_i >= 357
        ["3","5","7"].repeated_permutation (st) do |i|
            if i.count("7") >= 1 && i.count("5") >= 1&& i.count("3") >= 1
                ii = i.join("").to_i
                if ii <= n.to_i
                    count += 1
                end
            end
        end
    else
        count = 0
        break
    end
    if st == s
        break
    end
st += 1
end

puts count