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 <bits/stdc++.h>
using namespace std;
using ll=long long;
using vi=vector<int>;
using vvi=vector<vi>;
using vd=vector<double>;
using vvd=vector<vd>;
using vl=vector<ll>;
using vvl=vector<vl>;
using pii=pair<int,int>;
using vs=vector<string>;
#define rep(i,n) range(i,0,n)
#define range(i,a,n) for(int i=a;i<n;i++)
#define all(a) a.begin(),a.end()
#define LINF    	((ll)1ll<<60)
#define INF     	((int)1<<30)
#define EPS     	(1e-9)
#define MOD     	(1000000007)
#define fcout(a)	cout<<setprecision(a)<<fixed
#define fs 			first
#define sc			second
#define PI			3.141592653589793

template<class S,class T>ostream& operator<<(ostream&os,pair<S,T>p){os<<"["<<p.first<<", "<<p.second<<"]";return os;};
template<class S>auto&operator<<(ostream&os,vector<S>t){bool a=1; for(auto s:t){os<<(a?"":" ")<<s; a=0;} return os;}

ll n;
vi ans;

void rec(ll p){
    if(p<=n){
        auto s=to_string(p);
        if(s.find('3')!=-1 and s.find('5')!=-1 and s.find('7')!=-1)
            ans.push_back(p);
        rec(p*10+3);
        rec(p*10+5);
        rec(p*10+7);
    }
}

int main(){
	cin.tie(0);
   	ios::sync_with_stdio(false);
	
	cin>>n;
	rec(0);
	cout<<ans.size();
	return 0;
}