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 Lua (5.3.2) (judge verdict: Accepted)

local n = io.read("n")
-- local n = 999999999
local total = 0
local stack = {{0,0}}
while true do
	local len = #stack
	local one = stack[len]
	if not one then
		break
	end
	local value, mark = one[1], one[2]
	table.remove(stack, len)
	if value <= n then
		if mark == 7 then
			total = total + 1
		end
		table.insert(stack, {value * 10 + 3, mark | 1})
		table.insert(stack, {value * 10 + 5, mark | 2})
		table.insert(stack, {value * 10 + 7, mark | 4})
	end
end
print(total)