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<vector>
#include<algorithm>
#include<string>
#include<map>
#include<math.h>
#include<queue>
#include<deque>
#include<stack>
#include<cstdio>
#include<utility>
#include<set>
#include<list>
#include<cmath>
using namespace std;
using ll = long long;
using pii = pair<int, int>;
const int INF = 1e9;
int ans;
int N;
vector<ll>v;
void dfs(ll n, ll k){
	if (k > 1e9)return;
	int f[10] = {}, t = n;
	while (t) {
		f[t % 10]++;
		t /= 10;
	}
	if (f[3] && f[5] && f[7])v.push_back(n);
	dfs(n + 3 * k, k * 10);
	dfs(n + 5 * k, k * 10);
	dfs(n + 7 * k, k * 10);
}
int main() {
	ans = 0;
	cin >> N;
	dfs(0, 1);
	sort(v.begin(), v.end());
	ll i = 0;
	for (; i < v.size(); ++i) {
		if (v[i] > N)break;
	}
	cout << i << endl;
	return 0;
}