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 hantei753(int n);

int main(void)
{
	int i, N, answer=0;

	scanf("%d", &N);

	for (i = 357; i <= N; i += 2) {
		answer += hantei753(i);
	}
	printf("%d", answer);
	return 0;
}

int hantei753(int n)
{
	int flag3=0, flag5=0, flag7=0, Flag=1, amari;

	do {
		amari = n % 10;
		if (amari == 3)flag3 = 1;
		else if (amari == 5)flag5 = 1;
		else if (amari == 7)flag7 = 1;
		else Flag = 0;
		n = n / 10;
	} while (n > 0 && Flag);

	if (Flag == 1) {
		if ((flag3 + flag5 + flag7) == 3) {
			return 1;
		}
	}
	return 0;
}