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: Wrong Answer)

import Data.List
import Data.Char
-- import Debug.Trace

l = [3,5,7]

scan :: Int -> Int
scan n = iter (log10 n) where
    iter 2 = 0
    iter s = length ts + iter (s-1) where
        ts = filter (\e -> constraint e) (comb l s)
        constraint e = (all (\x -> elem x e) l) && (toN e < n)

toN :: [Int] -> Int
toN = iter 0 where
    iter ac [] = ac
    iter ac (x:xs) = iter (ac*10 + x) xs        

log10 :: Int -> Int
log10 n = iter 0 1 where
    iter e x
        | x >= n = e
        | otherwise = iter (e+1) (x*10)

comb :: [a] -> Int -> [[a]]
comb xs 0 = [[]]
comb xs n = [x:y| x <- xs, y <- (comb xs (n-1))]   

main :: IO() 
main = do
    s <- readLn :: IO Int
    let ans = scan s
    print ans