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 Haskell (GHC 7.10.3) (judge verdict: Accepted)

{-# OPTIONS_GHC -O2 -funbox-strict-fields #-}

main :: IO ()
main = do
  n <- readLn
  print $ solve n

solve :: Int -> Int
solve n = length $ takeWhile (<= n) n753s

n753s :: [Int]
n753s = filter is753 n753s'

is753 :: Int -> Bool
is753 x = find 3 x && find 5 x && find 7 x

find :: Int -> Int -> Bool
find n x
  | a == n = True
  | b == 0 = False
  | otherwise = find n b
  where
    a = x `mod` 10
    b = x `div` 10

n753s' :: [Int]
n753s' = go [3, 5, 7]
  where
    go xs = xs ++ go ys
      where
        ys = do
          x <- xs
          [append x 3, append x 5, append x 7]

append :: Int -> Int -> Int
append x y = x * 10 + y