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 (2.11.7) (judge verdict: Accepted)


import java.util.Scanner

object Main extends App {
  val sc = new Scanner(System.in)

  val n = sc.nextLong()

  val cnt = Stream.from(0)
    .map(i => Integer.toString(i, 4))
    .filter(s => s.contains('1') && s.contains('2') && s.contains('3') && !s.contains('0'))
    .map(s => s
      .replaceAll("3", "7")
      .replaceAll("1", "3")
      .replaceAll("2", "5"))
    .map(s => s.toLong)
    .takeWhile(n >= _)

  println(cnt.size)
}