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)

var ans = 0

fun main(args: Array<String>) {
    val n = readInputLine().toLong()

    dfs(n, 0L)

    println(ans)
}

fun readInputLine(): String {
    return readLine()!!
}

fun dfs(n: Long, s: Long) {
    if (s > n) {
        return
    }
    
    val sString = s.toString()
    if (sString.contains('7') && sString.contains('5') && sString.contains('3')) {
        ans++
    }
    
    dfs(n, s * 10L + 7L)
    dfs(n, s * 10L + 5L)
    dfs(n, s * 10L + 3L)
}