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;

typedef long long ll;
typedef pair<ll,ll> P;
const ll mod=1e9+7;
#define rep(i,N) for(ll i=0; i<(N); i++)
#define rep1(i,N) for(ll i=1; i<(N); i++)
#define pb push_back

ll N;
ll ans;
vector<vector<ll> > vv(60000);

bool check(ll n){
	ll nn=n;
	ll c3=0;
	ll c5=0;
	ll c7=0;
	while(1){
		if(nn%10==3) c3=1;
		if(nn%10==5) c5=1;
		if(nn%10==7) c7=1;
	   nn/=10;	
		if(nn==0) break;
	}
	if(c3&&c5&&c7) return true;
	else return false;
}

int main(){

cin.tie(0);
ios::sync_with_stdio(false);

cin>>N;

vv[0].pb(3);
vv[0].pb(5);
vv[0].pb(7);

for(ll i=1; i<=10; i++){
	for(ll j=0; j<vv[i-1].size(); j++){
		ll add1=3*pow(10,i)+vv[i-1][j];
		ll add2=5*pow(10,i)+vv[i-1][j];
		ll add3=7*pow(10,i)+vv[i-1][j];
		vv[i].pb(add1);
		vv[i].pb(add2);
		vv[i].pb(add3);
	}
}

for(ll i=2; i<=10; i++){
	for(ll j=0; j<vv[i].size(); j++){
		if(vv[i][j]<=N){
			if(check(vv[i][j])) ans++;
		}
	}
}

cout<<ans<<endl;

}