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: Wrong Answer)

#include<stdio.h>
int exp(int a, int b);

int main(void){
	
	int N;
	scanf("%d",&N);
	
	int i,j,k,a[10],product = 1,answer = 0,three;
	for(i = 1;i <= N;i++){
		
		product = 1;
		k = i;
		three = 0;
		for(j = 9;j >=0;j--){
			
			a[j] = k / exp(10, j);
			
			if(a[j] == 0){
			
				a[j] = 1;
			
			}
			
			if(a[j] == 3){
				
				three ++;
			
			}
			
			k = k %exp(10,j);
			
			product = product * a[j];
		}
		

		if((product %105 == 0)&&!(three == 0)){
			
			answer ++;
		
		}
	
	}
	printf("%d",answer);
	return 0;
	
}


int exp(int a, int b){
	
	int ans = 1,i;
	for(i=0; i<b; i++){
		
		ans = ans * a;
	
	}
	
	return ans;
	
}