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: Accepted)

#include <iostream>
#include <string>
#include <algorithm>
#include <cmath>
#include <stack>
#include <queue>
#include <map>
#include <numeric>
#include <type_traits>
#include <limits>
#include <random>

using namespace std;

using ll = long long;

#define rep(i,N) for(long long i = 0;i < (long long)N; ++i)

int N, ans;

int dfs(int n) {
	if (n > N) return 0;
	bool flag[3] = { false, false, false };
	string str = to_string(n);
	rep(i, str.length()) {
		if (str[i] == '3') flag[0] = true;
		if (str[i] == '5') flag[1] = true;
		if (str[i] == '7') flag[2] = true;
	}
	if (flag[0] && flag[1] && flag[2]) { 
		ans++;
	}

	if (n <= 100000000 && n <= N) {
		dfs(n * 10 + 3);
		dfs(n * 10 + 5);
		dfs(n * 10 + 7);
	}
	return 0;
}


int main() {
	cin >> N;
	dfs(0);
	cout << ans << endl;
	return 0;
}