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 PyPy2 (5.6.0) (judge verdict: Accepted)

N=raw_input()

l=len(N)

s="375"

ans=0
def func(t):
	global ans
	#print "func( ", t, " )", len(t)
	if len(t)>len(N):
		return
	else:
		for si in s:
			if si not in t:
				break
		else:
			if int(t)<=int(N):
				ans+=1
	func(t+"3")
	func(t+"5")
	func(t+"7")

	return ans

print func("")