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: Time Limit Exceeded)

#include <stdio.h>

int main( void ){
	long n,i,j,x,ans=0;
	int num[10] = {0};
	scanf("%ld",&n);
	for( i=357;i<=n;i++ ){
		for(j=0;j<10;j++) num[j]=0;
		j=i;
		while( j>0 ){
			x=j%10;
			num[x]++;
			j/=10;
			if(x!=3&&x!=5&&x!=7) j=-1;
		}
		if( j!=-1 && num[3]>0 && num[5]>0 && num[7]>0 ) ans++;
	}
	printf("%d\n",ans);			
	return 0;
}