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 Pascal (FPC 2.6.2) (judge verdict: Accepted)

const
	t:array[1..3] of char=('3','5','7');
var
	n:string;
	l,ans,b,j:longint;
procedure make(x:longint; s:string);
var
	i,a:longint;
begin
	if x=j+1 then
	begin
		if pos('3',s)=0 then exit;
		if pos('5',s)=0 then exit;
		if pos('7',s)=0 then exit;
		val(s,a);
		if a>b then exit;
		inc(ans);
		exit;
	end;
	for i:=1 to 3 do make(x+1,s+t[i]);
end;
begin
	read(b);
	str(b,n);
	l:=length(n);
	ans:=0;
	for j:=3 to l do make(1,'');
	writeln(ans);
end.