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 Kotlin (1.0.0) (judge verdict: Accepted)

fun main(args: Array<String>) {
    val n = readLine()!!.toInt()
    var count = 0
    val set = mutableSetOf(
            333, 335, 337, 353, 355, 357, 373, 375, 377,
            533, 535, 537, 553, 555, 557, 573, 575, 577,
            733, 735, 737, 753, 755, 757, 773, 775, 777
    )
    for (i in 1..6) {
        val temp = mutableSetOf<Int>().apply { addAll(set) }
        for (v in temp) {
            set.add((v.toString() + "3").toInt())
            set.add((v.toString() + "5").toInt())
            set.add((v.toString() + "7").toInt())
            set.add(("3" + v.toString()).toInt())
            set.add(("5" + v.toString()).toInt())
            set.add(("7" + v.toString()).toInt())
        }
    }
    val temp = set.filter { it.toString().contains('3')&&it.toString().contains('5') &&it.toString().contains('7')}
    println(temp.count { it <= n})
}