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>

int makenum(int num,int n);
int if753(int num);

int main()
{
    int n,i,j=0,flag=1;
	scanf("%d",&n);
	printf("%d",makenum(3,n)+makenum(5,n)+makenum(7,n));
}

int makenum(int num,int n)
{
	if(num>n)return 0;
	if(num>100000000)return if753(num);
	else return (if753(num)+makenum(num*10+3,n)+makenum(num*10+5,n)+makenum(num*10+7,n));
}

int if753(int num)
{
	int buk[10]={0};
	while(num!=0)
	{
		buk[num%10]++;
		num/=10;
	}
	if((buk[3])&&(buk[5])&&(buk[7]))return 1;
	else return 0;
}