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 (3.8.2) (judge verdict: Accepted)

from collections import deque

N = int(input())

def bfs(s):
    que = deque()
    que.append(s)
    cnt = 0
    while que.__len__() != 0:
        s = que.popleft()
        for ds in '753':
            ss = s + ds
            if int(ss) > N:
                continue
            if all(ss.count(i) > 0 for i in '753'):
                cnt += 1
            que.append(ss)
    return cnt

ans = 0
ans += bfs('3')
ans += bfs('5')
ans += bfs('7')

print(ans)