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;
#define INF 100000000
#define INFF 9223372036854775807
#define ll long long
#define REP(i,n) for(int i=0;i<n;i++)
#define REPP(i,m,n) for(int i=m;i<n;i++)
#define ALL(N) (N.begin(),N.end())
#define de cout << "debug" << endl;
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; }

ll ans ,n;

void solve(ll x,bool a,bool b,bool c){
    if(x>n)return;
    if(a && b && c) ans++;
    solve(x*10+3,1,b,c);
    solve(x*10+5,a,1,c);
    solve(x*10+7,a,b,1);
}

int main() {
    cin >> n;
    solve(0,0,0,0);
    cout << ans << endl;
}