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;
    i,sum : integer;
    e : boolean;
    
procedure sft(p : longint; d : integer; s,f,t : boolean);
begin
  if d = 0 then begin
    if s and f and t then if p <= n then sum := sum + 1 else e := true
  end else begin
    sft(p * 10 + 3, d - 1, s, f, true);
    sft(p * 10 + 5, d - 1, s, true, t);
    sft(p * 10 + 7, d - 1, true, f, t)
  end
end;
    
begin
  readln(n);
  sum := 0;
  e := false;
  for i := 3 to 9 do begin
    sft(0, i, false, false, false);
    if e then break;
  end;
  writeln(sum)
end.