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 rep(i, ini, n) for (int i = ini; i < n; i++)
#define _rep(i, ini, n) for (int i = ini; i >= n; i--)
#define ToEnd(a) a.begin(), a.end()
uint64_t MOD = 1000000007;

int64_t N;

bool Include(string S, int n){
    char c='0'+n;
    if(S.find(c)==string::npos) return false;
    else return true;
}

bool Check(int64_t num){
    string S=to_string(num);
    return Include(S,3) && Include(S,5) && Include(S,7);
}

void Solve(int64_t &ans, int64_t n=0, int i=1){
    if(i>10) return;

    if(n<=N && Check(n)) ans++;

    Solve(ans,10*n+3,i+1);
    Solve(ans,10*n+5,i+1);
    Solve(ans,10*n+7,i+1);
}

int main()
{
    cin >> N;

    int64_t ans = 0;
    Solve(ans);

    cout<<ans<<endl;
}