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)

N = input()
L = len(N)

dp = [[[[0] * 2 for _ in range(2)] for _ in range(2)] for _ in range(2)]
pp = [[[[0] * 2 for _ in range(2)] for _ in range(2)] for _ in range(2)]
dp[0][0][0][0] = 1

for i in range(L):
    pp, dp = dp, pp
    dp = [[[[0] * 2 for _ in range(2)] for _ in range(2)] for _ in range(2)]
    n = int(N[i])
    dp[0][0][0][1] += pp[0][0][0][1]
    dp[1][0][0][1] += pp[0][0][0][1] + pp[1][0][0][1]
    dp[0][1][0][1] += pp[0][0][0][1] + pp[0][1][0][1]
    dp[0][0][1][1] += pp[0][0][0][1] + pp[0][0][1][1]
    dp[1][1][0][1] += pp[1][0][0][1] + pp[0][1][0][1] + pp[1][1][0][1] * 2
    dp[1][0][1][1] += pp[1][0][0][1] + pp[0][0][1][1] + pp[1][0][1][1] * 2
    dp[0][1][1][1] += pp[0][1][0][1] + pp[0][0][1][1] + pp[0][1][1][1] * 2
    dp[1][1][1][1] += pp[1][1][0][1] + pp[1][0][1][1] + pp[0][1][1][1] + pp[1][1][1][1] * 3
    if n > 0:
        dp[0][0][0][1] += pp[0][0][0][0]
    if n > 3:
        dp[1][0][0][1] += pp[1][0][0][0] + pp[0][0][0][0]
        dp[1][1][0][1] += pp[1][1][0][0] + pp[0][1][0][0]
        dp[1][0][1][1] += pp[1][0][1][0] + pp[0][0][1][0]
        dp[1][1][1][1] += pp[1][1][1][0] + pp[0][1][1][0]
    if n > 5:
        dp[0][1][0][1] += pp[0][1][0][0] + pp[0][0][0][0]
        dp[1][1][0][1] += pp[1][1][0][0] + pp[1][0][0][0]
        dp[0][1][1][1] += pp[0][1][1][0] + pp[0][0][1][0]
        dp[1][1][1][1] += pp[1][1][1][0] + pp[1][0][1][0]
    if n > 7:
        dp[0][0][1][1] += pp[0][0][1][0] + pp[0][0][0][0]
        dp[1][0][1][1] += pp[1][0][1][0] + pp[1][0][0][0]
        dp[0][1][1][1] += pp[0][1][1][0] + pp[0][1][0][0]
        dp[1][1][1][1] += pp[1][1][1][0] + pp[1][1][0][0]
    if n == 0:
        dp[0][0][0][0] += pp[0][0][0][0]
    if n == 3:
        dp[1][0][0][0] += pp[1][0][0][0] + pp[0][0][0][0]
        dp[1][1][0][0] += pp[1][1][0][0] + pp[0][1][0][0]
        dp[1][0][1][0] += pp[1][0][1][0] + pp[0][0][1][0]
        dp[1][1][1][0] += pp[1][1][1][0] + pp[0][1][1][0]
    if n == 5:
        dp[0][1][0][0] += pp[0][1][0][0] + pp[0][0][0][0]
        dp[1][1][0][0] += pp[1][1][0][0] + pp[1][0][0][0]
        dp[0][1][1][0] += pp[0][1][1][0] + pp[0][0][1][0]
        dp[1][1][1][0] += pp[1][1][1][0] + pp[1][0][1][0]
    if n == 7:
        dp[0][0][1][0] += pp[0][0][1][0] + pp[0][0][0][0]
        dp[1][0][1][0] += pp[1][0][1][0] + pp[1][0][0][0]
        dp[0][1][1][0] += pp[0][1][1][0] + pp[0][1][0][0]
        dp[1][1][1][0] += pp[1][1][1][0] + pp[1][1][0][0]


print(sum(dp[1][1][1]))