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)

import java.util.*
import kotlin.system.exitProcess

var n = 0L
var ans = 0

fun main(args: Array<String>) {
    val sc = Scanner(System.`in`)
    n = sc.nextLong()
    for (i in 1..Int.MAX_VALUE) {
        dfs(i, "")
    }

}

fun dfs(rest: Int, s: String) {
    if (rest == 0) {
        if (s.toLong()> n) {
            println(ans)
            exitProcess(0)
        }
        for (v in "357") {
            if (v !in s) {
                return
            }
        }
        ans++
    } else {
        for (c in "357") {
            dfs(rest - 1, s + c)
        }
    }
}