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)

var s:string;
tot,nn:longint;
a:array[1..10]of integer;
b:array[1..10]of 0..1;
procedure dfs(n,x:longint);
var num,i:longint;
begin 
	if (n>=4) and (x<=nn) then 
	begin 
		{for i:=1 to n-1 do write(a[i]);
		writeln;}
		fillchar(b,sizeof(b),0);
		for i:=1 to n-1 do b[a[i]]:=1;
		if (b[3]=1) and (b[5]=1) and(b[7]=1) then inc(tot);
		
	end;
	if n>length(s) then exit;
		a[n]:=3;
		dfs(n+1,x*10+3);
		a[n]:=5;
		dfs(n+1,x*10+5);
		a[n]:=7;
		dfs(n+1,x*10+7);
end;
begin 
    readln(s);
	val(copy(s,1,length(s)),nn);
    fillchar(a,sizeof(a),0);
    tot:=0;
    dfs(1,0);
    write(tot);
end.