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 Java8 (OpenJDK 1.8.0) (judge verdict: Accepted)

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.*;

public class Main {
    private static Scanner sc;
    public static void main(String[] args) {
        Main instance = new Main();
        sc = instance.new Scanner();
        instance.solve();
    }
    long N;

    private void solve() {
        try {
            this.N = sc.nextInt();
            System.out.println(dfs("0"));

        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    private long dfs (String s) {
        if (Long.parseLong(s) > N) return 0;
        long ret;
        if (s.contains("7") && s.contains("5") && s.contains("3")) {
            ret = 1;
        } else {
            ret = 0;
        }
        List<String> list = new ArrayList<>();
        list.add("7");list.add("5");list.add("3");
        for (String ss: list) {
            if (s.equals("0")) {
                ret += dfs(ss);
            } else {
                ret += dfs(s + ss);
            }
        }
        return ret;
    }


    private int gcd(int a, int b) {
        if (a < b) return gcd(b, a);
        if (b == 0) return a;
        return gcd(b, a%b);
    }

    private int gcd(int[] param) {
        final int len = param.length;
        int g = gcd(param[0], param[1]);
        for (int i = 1; i < len - 1; i++) {
            g = gcd(g, param[i+1]);
        }
        return g;
    }

    private class Scanner {
        String[] s;
        int i;
        BufferedReader br;
        String regex = " ";

        public Scanner() {
            s = new String[0];
            i = 0;
            br = new BufferedReader(new InputStreamReader(System.in));
        }

        @Override
        protected void finalize() throws Throwable {
            try {
                super.finalize();
            } finally {
                destruction();
            }
        }

        private void destruction() throws IOException {
            if (br != null) br.close();
        }

        public String next() throws IOException {
            if (i < s.length) return s[i++];
            String st = br.readLine();
            while (st == "") st = br.readLine();
            s = st.split(regex, 0);
            i = 0;
            return s[i++];
        }

        public int nextInt() throws NumberFormatException, IOException {
            return Integer.parseInt(next());
        }

        public Long nextLong() throws NumberFormatException, IOException {
            return Long.parseLong(next());
        }

        public Double nextDouble() throws NumberFormatException, IOException {
            return Double.parseDouble(next());
        }
    }
}