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
	n:Longint;
function f(x:int64;a,b,c:Longint):Longint;
begin
	f:=0;
	if x<=n then f:=a*b*c+f(x*10+3,1,b,c)+f(x*10+5,a,1,c)+f(x*10+7,a,b,1);
end;
begin
	read(n);
	if n>700000000 then writeln(17656+f(7,0,0,1))
	else if n>500000000 then writeln(8828+f(5,0,1,0))
	else writeln(f(0,0,0,0));
end.