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)

# C
import itertools
tmp = input()
siz = len(tmp)
N = int(tmp)

table = ['3','5','7']
cnt = 0 
for i in range(3, siz):
    #print("i", i)
    for combi in itertools.product(table, repeat=i):
        #print(combi)
        cnt += 1 if len(set(combi)) == 3 else 0

for combi in itertools.product(table, repeat=siz):
    # combiを数字に変換
    cur = 0
    for i,v in enumerate(combi[::-1]):
        cur += 10**i * int(v)
    #print(cur, combi)
    # Nと比較
    if N >= cur:
        cnt += 1 if len(set(combi)) == 3 else 0
        

print(cnt)