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 = int(input())
def n_ary(l,d): # リストl中の文字でd桁までを全列挙(sorted)
    if d == 1:
        return(l)
    n = len(l)
    ll = n_ary(l,d-1)
    lll = []
    for i in l:
        for j in ll[n*(n**(d-2)-1)//(n-1):]:
            lll.append(i+j)
    return(ll+lll)
possible = [i.replace('0','3').replace('1', '5').replace('2','7') for i in n_ary(['0','1','2'],9)] # 制約が10^9なので9
print(len([int(i) for i in possible if ('3' in i and '5' in i and '7' in i and int(i) <= N)]))