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>
typedef long long ll;
using namespace std;
ll MOD = 1e9+7;

#define vec     vector<int>
#define vecll   vector<ll>
#define vec2    vector<vector<int>>
#define vec2ll  vector<vector<ll>>
#define vpair   vector<pair<int, int>>
#define vpairll vector<pair<ll, ll>>

#define rep(i,n)         for(ll i=(ll)0; i<(ll)n; i++)
#define REP(i,m,n)       for(ll i=(ll)m; i<(ll)n; i++)
#define arr(var, n)      vec var(n); rep(i,n){cin >> var[i];}
#define arrll(var, n)    vecll var(n); rep(i,n){cin >> var[i];}
#define all(var)         (var).begin(), (var).end()
#define sortall(var)     sort(all(var))
#define f_sum(var)       accumulate(all(var), 0)
#define f_sumll(var)     accumulate(all(var), 0LL)
#define chmin(v1, v2)    v1 = min(v1, v2)
#define chmax(v1, v2)    v1 = max(v1, v2)
#define mpair(v1, v2)    make_pair(v1, v2)
#define pb(var)          push_back(var)
#define prt(var)         cout << var << "\n"
#define scn(var)         cin >> var;
#define pYes()           prt("Yes")
#define pNo()            prt("No")
#define prtd(n, var)     cout << fixed << setprecision(n) << var << "\n"
#define prt2(v1, v2)     cout << v1 << " " << v2 << "\n"
#define prt3(v1, v2, v3) cout << v1 << " " << v2 << " " << v3 << "\n"
#define prtall(var)      rep(i,var.size()){cout << var[i] << " ";} cout << "\n"
//----------------------------------------------------------------

int main(void) {
  int n;
  cin >> n;

  priority_queue<ll, vector<ll>, greater<ll>> q, r;
  q.push(3);
  q.push(5);
  q.push(7);
  r.push(3);
  r.push(5);
  r.push(7);

  while(r.size()<60000){
    ll tmp = q.top();
    q.push(tmp*10+3);
    q.push(tmp*10+5);
    q.push(tmp*10+7);
    r.push(tmp*10+3);
    r.push(tmp*10+5);
    r.push(tmp*10+7);
    q.pop();
  }

  int ans = 0;

  while(r.top()<=n){
    string s = to_string(r.top());
    r.pop();
    bool is_3=false, is_5=false, is_7=false;
    rep(i,s.size()){
      if(s[i]=='3') is_3=true;
      if(s[i]=='5') is_5=true;
      if(s[i]=='7') is_7=true;
    }
    if(is_3 && is_5 && is_7) ans++;

  }

  prt(ans);
}