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# (Mono 4.6.2.0) (judge verdict: Accepted)

using System;
using System.Collections.Generic;
class Program
{
	static void Main(string[] args)
	{
		int A = int.Parse(Console.ReadLine());
		int n = 333;
		int ct = 0;
		while(true){
			//Console.WriteLine(n);
			if(n%10==3 || n%10==5){
				n += 2;
			} else {
				if(n/10%10!=7){
					n += 16;
				} else {
					if(n/100%10!=7){
						n += 156;
					} else {
						if(n/1000%10==0){
							n += 2556;
						} else if(n/1000%10==3 || n/1000%10 == 5){
							n += 1556;
						} else {
							if(n/10000%10==0){
								n += 25556;
							} else if(n/10000%10==3 || n/10000%10 == 5){
								n += 15556;
							} else {
								if(n/100000%10==0){
									n += 255556;
								} else if(n/100000%10==3 || n/100000%10 == 5){
									n += 155556;
								} else {
									if(n/1000000%10==0){
										n += 2555556;
									} else if(n/1000000%10==3 || n/1000000%10 == 5){
										n += 1555556;
									} else {
										if(n/10000000%10==0){
											n += 25555556;
										} else if(n/10000000%10==3 || n/10000000%10 == 5){
											n += 15555556;
										} else {
											if(n/100000000%10==0){
												n += 255555556;
											} else if(n/100000000%10==3 || n/100000000%10 == 5){
												n += 155555556;
											} else {
												n = 1000000000;
											}
										}
									}
								}
							}
						}
					}
				}
			}
			if(n>A){
				break;
			}
			int ct3 = 0;
			int ct5 = 0;
			int ct7 = 0;
			int na = n;
			for(var i=0;i<=9;i++){
				if(na/(int)Math.Pow(10,i)%10==3){
					ct3 += 1;
				}
				if(na/(int)Math.Pow(10,i)%10==5){
					ct5 += 1;
				}
				if(na/(int)Math.Pow(10,i)%10==7){
					ct7 += 1;
				}
			}
			if(ct3>0&&ct5>0&&ct7>0){
				ct += 1;
				//Console.WriteLine(n+"a");
			}
		}
		Console.WriteLine(ct);
	}
}