import java.util.*;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int a = sc.nextInt();
        int b = sc.nextInt();
        int count = 0;
        for (int i = 23; i <= 25; i++) {
            if (i < a || i > b) {
                count++;
            }
        }
        System.out.println(count);
    }
}