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 <list>
#include <set>
#include <map>
#include <queue>
#include <stack>
#include <cctype>
#include <climits>
#include <string>
#include <bitset>
#include <cfloat>
#include <unordered_set>
#pragma GCC optimize("Ofast")
using namespace std;
typedef long double ld;
typedef long long int ll;
typedef unsigned long long int ull;
typedef vector<int> vi;
typedef vector<char> vc;
typedef vector<bool> vb;
typedef vector<double> vd;
typedef vector<string> vs;
typedef vector<ll> vll;
typedef vector<pair<int,int> > vpii;
typedef vector<vector<int> > vvi;
typedef vector<vector<char> > vvc;
typedef vector<vector<string> > vvs;
typedef vector<vector<ll> > vvll;
#define rep(i,n) for(int i = 0; i < (n); ++i)
#define rrep(i,n) for(int i = 1; i <= (n); ++i)
#define drep(i,n) for(int i = (n) - 1; i >= 0; --i)
#define fin(ans) cout << (ans) << '\n'
#define STI(s) atoi(s.c_str())
#define mp(p,q) make_pair(p, q)
#define pb(n) push_back(n)
#define all(a) a.begin(), a.end()
#define rall(a) a.rbegin(), a.rend()
#define Sort(a) sort(a.begin(), a.end())
#define Rort(a) sort(a.rbegin(), a.rend())
#define MATHPI acos(-1)
#define itn int
template <class T> inline bool chmax(T& a,T b){if(a<b){a=b;return 1;} return 0;}
template <class T> inline bool chmin(T& a,T b){if(a>b){a=b;return 1;} return 0;}
struct io{io(){ios::sync_with_stdio(false);cin.tie(0);}};
const ll MOD = 1000000007;
const double EPS = 1e-9;
const int INF = INT_MAX;
const ll LLINF = 1LL<<60;

set<ll> s;

void rec(ll n){
    s.insert(n);
    n*=10;
    if(n<1000000000){
        rec(n+3);
        rec(n+5);
        rec(n+7);
    }
}

bool exs(int n){
    int san=0;
    int go=0;
    int nana=0;
    while(n>0){
        int t=n%10;
        n/=10;
        if(t==3)san++;
        else if(t==5)go++;
        else if(t==7)nana++;
    }
    if(go>0&&san>0&&nana>0)return 1;
    else return 0;
}

int main(void) {

    int n;
    cin>>n;
    // vi v{3,5,7};
        
    // do{
    //     // rec(v[0]*100+v[1]*10+v[2]);
    // }while(next_permutation(all(v)));
    rec(3);
    rec(5);
    rec(7);
    int ans=0;
    for(auto it=s.begin();it!=s.end();it++){
        if(*it<=n){
            if(exs(*it))ans++;
        }
    }
    fin(ans);
}