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 <cstdio>
#include <vector>
#include <map>
#include <set>
#include <cmath>
#include <iomanip>
using namespace std;
#define reps(i,s,n) for(int i = s; i < n; i++)
#define rep(i,n) reps(i,0,n)
#define Rreps(i,n,e) for(int i = n - 1; i >= e; --i)
#define Rrep(i,n) Rreps(i,n,0)
#define ALL(a) a.begin(), a.end()
#define endl "\n"
typedef long long ll;
#define traceV(v) for(auto x:v)cout<<x<<" ";cout<<endl
#define traceM(mp) for(auto x:mp)cout<<x.first<<" "<<x.second<<endl
#define MOD 1000000007

ll N;
ll res = 0;

void func(ll cur) {
  if(cur > N) return;

  string s = to_string(cur);
  int is753 = 0b000;
  for(auto c:s) {
    if(c == '7') is753 |= 0b100;
    if(c == '5') is753 |= 0b010;
    if(c == '3') is753 |= 0b001;
  }
  if(is753 == 0b111) {++res;}

  func(cur*10+7);

  func(cur*10+5);

  func(cur*10+3);
}

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

  // 再帰による全探索
  // https://drken1215.hatenablog.com/entry/2019/04/03/125400
  cin>>N;
  func(0);
  cout << res << endl;

  return 0;
}