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 <algorithm>
#include <string>
#include <vector>
#include <functional>
#include <bitset>
#include <cmath>
#include <stack>
#include <iomanip>
#include <map>
#include <math.h>
typedef long long ll;
using namespace std;
const int MOD = 1000000007;

ll GCD(ll a, ll b) { return b ? GCD(b, a%b) : a; }

int N;

void func(ll cur,ll use, ll &counter)
{
    if(cur > N) return;
    if(use == 0b111) counter++;

    func(cur*10 + 7, use | 0b001, counter);
    func(cur*10 + 5, use | 0b010, counter);
    func(cur*10 + 3, use | 0b100, counter);
}

int main()
{
    cin >> N;
    ll res = 0;
    func(0,0,res);
    cout << res << endl;
}