import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int A = sc.nextInt();
		int B = sc.nextInt();
		sc.close();
		int []d = {23, 24, 25};
		int cnt = 0;
		for(int i : d) {
			if(!(i >= A && i <= B)) {
				cnt++;
			}
		}
		System.out.println(cnt);
	}
}