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<algorithm>
using lint=int64_t;
using namespace std;

int dp[10][2][2][2][2];

int rec(string &N,int n=0,int tight=1,int t=0,int f=0,int s=0,int o=1)
{
	if(o==0)
		return 0;
	
	if(n==N.size())
	{
		if(t&f&s)
			return 1;
		else
			return 0;
	}

	if(dp[n][tight][t][f][s]!=-1)
		return dp[n][tight][t][f][s];

	int maxi=9;
	if(tight)maxi=N[n]-'0';

	int ret=0;
	for(int i=0;i<=maxi;i++)
		ret+=rec(N,n+1,tight & i==maxi,t | i==3,f | i==5,s | i==7,
			( (i|t|f|s)==0  | (i==3 | i==5 | i==7) )
		);

	dp[n][tight][t][f][s]=ret;
	return ret;
}

int main()
{
	for(int i=0;i<10;i++)
	for(int j=0;j<2;j++)
	for(int k=0;k<2;k++)
	for(int l=0;l<2;l++)
	for(int m=0;m<2;m++)
		dp[i][j][k][l][m]=-1;

	string N;
	cin >> N;

	cout << rec(N) << endl;
	return 0;
}