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++14 (GCC 5.4.1) (judge verdict: Runtime Error)

#include <iostream>
#include <string>
using namespace std;

bool check(string& s, int n) {
	if (stoi(s) > n) {
		return false;
	}
	for (char c : "753") {
		if (s.find(std::to_string(c)) == string::npos) {
			return false;
		}
	}
	return true;
}

int dfs(string s, int n) {
	int res = 0;
	if (!s.empty()) {
		if (check(s, n)) {
			++res;
		} else if (stoi(s) > n) {
			return 0;
		}
	}
	for (char next : "753") {
		res += dfs(s + next, n);
	}
	return res;
}

int solve(int n) {
	return dfs("", n);
}

int main() {
	int n;
	cin >> n;

	cout << solve(n) << endl;

	return 0;
}