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 PyPy3 (2.4.0) (judge verdict: Accepted)

def abc114_c():
  n = int(input())

  def bit_mask(n):
    b, d = 4, 9  # bit, digit
    arr = []
    for i in range(d-1, -1, -1):
      arr.append(n // (b**i))
      n = n % (b**i)
    ret = str(int(''.join(map(str, arr))))
    return ret

  def decode753(arr):
    ret = ''.join(map(str, arr)).replace('3','7').replace('2','5').replace('1','3')
    return int(ret)

  ans = 0
  b, d = 4, 9
  for m in range(b**d):
    mask = bit_mask(m)
    if mask.count('0') == 0 and mask.count('1') > 0 and mask.count('2') > 0 and mask.count('3') > 0:
      x = decode753(mask)
      if x <= n: ans += 1
      else: break
  print(ans)

abc114_c()