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 Scala (2.13.1) (judge verdict: Accepted)

import scala.collection.mutable._

object Main extends App {
    val ns = ArrayBuffer(
      Array(7,5,3): _*
    )
  
    val n = io.StdIn.readLine.toInt
    
    1.to(9-1).foreach { i => 
      val newNs = ArrayBuffer[Int]()
      List(7,5,3).foreach { suffix =>
        ns.foreach { n =>
		  val m = n * 10 + suffix
          newNs += m
        }
      }
      ns ++= newNs
	}
    
    println(ns.sortBy(identity).distinct.count {
      x => 
        val xs = x.toString
        x <= n &&
        xs.contains("7") && 
        xs.contains("5") && 
        xs.contains("3")
    })
}