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<cstdio>
#include<algorithm>
#include<cmath>
#include<vector>
#include<set>
#include<map>
#include<queue>
#include<stack>
#include<cctype>
#include<climits>
#include<string>
#include<bitset>
#include<cfloat>
#include<iomanip>
#include<numeric>

//#define int long long
#define repi(i,start,end) for(int (i)=(start),TemPNuM=(int)(end);(i)<TemPNuM;++(i))
#define rep(i,end) repi((i),0,(end))
#define rfor(x,v) for(auto& (x) : (v))
#define all(x) (x).begin(),(x).end()
#define rall(x) (x).rbegin(),(x).rend()
#define fsort(v,lambda) sort(all((v)),(lambda))
#define vin(v) rep(i,(v).size())cin >> (v)[i];
#define vpin(v) rep(i,(v).size())cin>>v[i].first>>v[i].second

using namespace std;
using ll =  long long;
using pint =  pair<int,int>;
using vint = vector<int>;
using vvint = vector<vint>;
using vpint = vector<pint>;

template<class T>bool chmax(T &a, const T &b) { if (a<b) { a=b; return 1; } return 0; }
template<class T>bool chmin(T &a, const T &b) { if (b<a) { a=b; return 1; } return 0; }
template<class T>void put_double(T a){if(cout.precision()!=12)cout<<setprecision(12);cout<<a<<endl;}
template<class T>void print(T a){cout << a << endl;}
//lambda: [](int x, int y){return x<y;}


signed main(void) {
    int n;
    vector<vector<string>> s(10, vector<string>(1));
    cin >> n;
    s[0][0] = "";
    repi(i, 1, 10) {
        rfor(x, s[i - 1]) {
            s[i].push_back(x + "3");
            s[i].push_back(x + "5");
            s[i].push_back(x + "7");
        }
    }
    set<string> ans;
    rfor(v, s) {
        rfor(str, v) {
            if(str.find("3") == string::npos) continue;
            if(str.find("5") == string::npos) continue;
            if(str.find("7") == string::npos) continue;
            if(stoi(str) > n) continue;
            ans.insert(str);
        }
    }
    print(ans.size());


    return 0;
}