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 <vector>
#include <algorithm>
#include <string>
#include <set>
#include <map>
#include <cmath>
using namespace std;
#define rep(i,n) for(int i=0;i<n;++i)
vector<string> s;
void p(int d,string r){
	if (d==9)
		return;
	s.push_back(r+"3");
	p(d+1,r+"3");
	s.push_back(r+"5");
	p(d+1,r+"5");
	s.push_back(r+"7");
	p(d+1,r+"7");
}

bool c(int a){
	int p=0;
	bool s=0,c=0,t=0;
	rep(i,10){
		p=(int)(a/pow(10,i))%10;
		if (p==3)
			c=1;
		if (p==5)
			s=1;
		if (p==7)
			t=1;
	}
	return (s&c&t);
}
int main(){
	int n;
	int cnt=0;
	int i=0;
	cin >>n;
	p(0,"");
	for (auto i:s){
		int t=atoi(i.c_str());
		if (t<=n){
			if (c(t))cnt++;
		}
	}
	cout <<cnt;
}