import java.util.*;
import java.lang.*;
import java.io.*;

public class Main {
	public static void main (String[] args) throws java.lang.Exception
	{
		// your code goes here
		// 入力
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();
		
		// カウント
		int count = 0;
		if(N < 100){
			count = N / 3 - 3;
		}else{
			count = 30;
			int id = 16;
			long num = baseConvert(id) * 3L;
			while(num <= N){
				count++;
				id++;
				num = baseConvert(id) * 3L;
			}
		}
		
		// 出力
		System.out.println(count);
	}

	// 10進数→4進数変換関数
	public static int baseConvert(int num){
		int output = 0;
		int digit = 1;
		while(num > 0){
			int amari = num % 4;
			output += amari * digit;
			num = num / 4;
			digit *= 10;
		}
		
		return output;
	}

}