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 C (GCC 5.4.1) (judge verdict: Accepted)

#include<stdio.h>
long long N, ans;
int ossu(long long a, long long b3, long long b5, long long b7){
	if(a>N){return;}
	if(b3+b5+b7==3){ans++;}
	ossu(a*10+3, 1, b5, b7);
	ossu(a*10+5, b3, 1, b7);
	ossu(a*10+7, b3, b5, 1);
}
int main(){
	scanf("%lld", &N);
	ossu(0, 0, 0, 0);
	printf("%lld\n", ans);
}