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 Python (3.4.3) (judge verdict: Accepted)

import sys
IS = lambda: sys.stdin.readline().rstrip()
II = lambda: int(IS())
MII = lambda: list(map(int, IS().split()))
from collections import deque

def main():
    n = II()
    cnt = 0
    dq = deque(['3', '5', '7'])
    while dq:
        d = dq.popleft()
        if int(d) > n: break
        if '7' in d and '5' in d and '3' in d:
            cnt += 1
        dq.append(d+'3')
        dq.append(d+'5')
        dq.append(d+'7')
    print(cnt)

if __name__ == '__main__':
    main()