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 PHP (5.6.30) (judge verdict: Wrong Answer)

<?php
//error_reporting(0);
$N = trim(fgets(STDIN));
//list($N,$K) = explode(" ",trim(fgets(STDIN)));
//$a = explode(" ",trim(fgets(STDIN)));
//$H = explode(" ",trim(fgets(STDIN)));

function combine() {
    $args = func_get_args();

    $a = array_shift($args);
    $b = array_shift($args);

    $result = array();
    foreach ($a as $val1) {
        foreach ($b as $val2) {
            $result[] = array_merge((array)$val1, (array)$val2);
        }
    }

    if (count($args) > 0) {
        foreach ($args as $arg) {
            $result = combine($result, $arg);
        }
    }

    return $result;
}
$p = [3,5,7];
$n=0;
switch(strlen($N)) {
case 9:
  $n+=ncnt(combine($p,$p,$p,$p,$p,$p,$p,$p,$p));
case 8:
  $n+=ncnt(combine($p,$p,$p,$p,$p,$p,$p,$p));
case 7:
  $n+=ncnt(combine($p,$p,$p,$p,$p,$p,$p));
case 6:
  $n+=ncnt(combine($p,$p,$p,$p,$p,$p));
case 5:
  $n+=ncnt(combine($p,$p,$p,$p,$p));
case 4:
  $n+=ncnt(combine($p,$p,$p,$p));
case 3:
  $n+=ncnt(combine($p,$p,$p));
}
printf("%d\n",$n);

function ncnt($a) {
  global $N;
  foreach($a as $v) {
    $s = implode("",$v);
    if ((strpos($s,"3")!==false)
    && (strpos($s,"5")!==false)
    && (strpos($s,"7")!==false)) {
      if ($s < $N) {
        $l[]=$s;
      }
    }
  }
  return count($l);
}