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: Time Limit Exceeded)

cnt = 0
def dfs(x,y,n)
    k = 10 * x + y
    if k > n
        return ;
    end
    if n / 100 >= 1
        three = 0,five = 0, seven = 0
  		t = k
        while t > 0
            if t % 10 == 3
                three = 1
            elsif
                t % 10 == 5
                five = 1
            else
                seven = 1
            end
        end
        if three == 1 && five == 1 && seven == 1
            cnt += 1
        end
    end
end


n = gets.to_i
dfs(0,3,n)
dfs(0,5,n)
dfs(0,7,n)
puts cnt