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: Time Limit Exceeded)

#include <iostream>
#include <cstdio>
#include <string>
#include <vector>
#include <iterator>  // std::back_inserter()
#include <set>
#include <algorithm>  // std::copy()
#include <functional>  // std::greater<T>()
#include <utility>  // std::swap()
#include <numeric>  // accumulate(ALL(vec), 0)  0 は初期値
#include <cmath>
#include <climits>  // INT_MIN
#include <cctype>  // std::isdigit()
using namespace std;

#define ALL(obj) (obj).begin(), (obj).end()
#define REP(i, n) for (int i=0; i < (int)(n); i++)  // 0 ~ n-1
#define REPN(i, n) for (int i=1; i <= (int)(n); i++)  // 1 ~ n
#define MIN(vec) min_element(ALL((vec)))  // イテレータのため、値を取り出すときは * を先頭につける
#define MAX(vec) max_element(ALL((vec)))
#define IDX(vec, element_iter) distance((vec).begin(), element_iter)
#define SUM(vec) accumulate(ALL((vec)), 0)  // 0 は初期値
#define COPY(vec1, vec2) copy(ALL(vec1), back_inserter(vec2))  // vec1をvec2にコピーする vec2は空にしておく必要あり
typedef long long ll;

const int MOD = 1000000007;  // 1 000 000 007


int is753(int num) {
    vector<int> vec(10);
    while (num != 0) {
        int amari = num%10;
        if (amari != 3 and amari != 5 and amari != 7) {
            return false;
        } else {
            vec[amari]++;
        }
        num /= 10;
    }
    
    if (vec[3] >= 1 and vec[5] >= 1 and vec[7] >= 1) {
        return true;
    } else {
        return false;
    }
}

int main() {
    cin.tie(0);
    ios::sync_with_stdio(false);

    // input
    int N;
    cin >> N;
    
    // calculation
    int sum = 0;
    REPN(i, N) {
        if (is753(i)) {
            sum++;
        }
    }
    
    cout << sum << "\n";
    
    return 0;
}