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)

#pragma GCC target("avx")
#pragma GCC optimize("O3")
#pragma GCC optimize("unroll-loops")
#include <cctype>
#include <cerrno>
#include <cfloat>
#include <ciso646>
#include <climits>
#include <clocale>
#include <cmath>
#include <csetjmp>
#include <csignal>
#include <cstdarg>
#include <cstddef>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <ctime>

#include <algorithm>
#include <bitset>
#include <complex>
#include <deque>
#include <exception>
#include <fstream>
#include <functional>
#include <iomanip>
#include <ios>
#include <iosfwd>
#include <iostream>
#include <istream>
#include <iterator>
#include <limits>
#include <list>
#include <locale>
#include <map>
#include <memory>
#include <new>
#include <numeric>
#include <ostream>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <stdexcept>
#include <streambuf>
#include <string>
#include <typeinfo>
#include <utility>
#include <valarray>
#include <vector>
#include <regex>
#define rep(i,n) for(int i = 0; i < n; i++)
#define reps(i,j,n) for(int i = j; i < n; i++)
#define rrep(i,j,n) for(int i = j-1; i >= n; i--)
#define prec(n) fixed << setprecision(n)
#define print_array(v) rep(__k, v.size()) { cout << v[__k]; if(__k != v.size()-1) cout << " "; else cout << endl; }
#define YesorNo(a) printf(a?"Yes\n":"No\n")
#define fi first
#define se second
#define endl "\n"
using namespace std;

constexpr int inf = 2147483647;
constexpr int64_t inf64 = 9223372036854775807;
constexpr int mod = 1e9+7;

int64_t n, res = 0LL;
void dfs(int64_t num, bool ok3, bool ok5, bool ok7){
  if(num > n) return;
  if(ok3 && ok5 && ok7) res++;
  dfs(num*10+3, true, ok5,  ok7 );
  dfs(num*10+5, ok3,  true, ok7 );
  dfs(num*10+7, ok3,  ok5,  true);
}

signed main(){
  cin >> n;
  dfs(0, false, false, false);
  cout << res << endl;
  return 0;
}