import java.util.*;

public class Main {
    public static void main(String[] args) {
		Scanner scan = new Scanner(System.in);
		int n = scan.nextInt();
		int count = 0;
		for(int i = 1 ; i <= n ; i++){
			if( i % 10 == 8 || i / 10 == 8 ){
				count++; 
			}
		}
		System.out.println(count);
    }
}