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 <bits/stdc++.h>
#define PI 				acos(-1)
#define mp				make_pair
#define pb				push_back
#define all(a)			(a).begin(), (a).end()
#define srt(a)			sort(all(a))
#define mem(a, h)		memset(a, (h), sizeof(a))
#define f 				first
#define s 				second
#define MOD				1000000007
#define MOD1			998244353
#define EPS				1e-9
#define fore(i, b, e)	for(int i = b; i < e; i++)
#define forg(i, b, e, m)	for(int i = b; i < e; i+=m)

using namespace std;

typedef long long 		ll;
typedef unsigned long long 		ull;
typedef pair<int, int>  ii;
typedef vector<int>     vi;
typedef vector<ii>      vii;
typedef vector<ll>      vll;
const int tam = 10000010;
map<ll, int> dp;
int n;
int f(ll num)
{
	if(dp[num] != 0) return dp[num];
	if(num > n) return 0;
	bool bo[] = {0,0,0};
	ll ax = num;
	while(ax > 0)
	{
		if(ax%10 == 3) bo[0] = 1;
		if(ax%10 == 5) bo[1] = 1;
		if(ax%10 == 7) bo[2] = 1;
		ax /= 10;
	}
	return dp[num] = (bo[0]&&bo[1]&&bo[2]) + f(num*10 + 5) + f(num*10 + 3) + f(num*10 + 7);
}
int main()
{
	ios::sync_with_stdio(false); cin.tie(0);
	//freopen("asd.txt", "r", stdin);
	//freopen("asd.txt", "w", stdout);
	cin>>n;
	cout<<f(5) + f(7) + f(3)<<'\n';
	return 0;
}

// read the question correctly (is y a vowel? what are the exact constraints?)
// look out for SPECIAL CASES (n=1?) and overflow (ll vs int?) ARRAY OUT OF BOUNDSS2