import java.util.*;

public class Main {
    public static void main(String[] args) throws Exception {
        Scanner in = new Scanner(System.in);
        // 合宿の日程
        List<Integer> camp = Arrays.asList(23, 24, 25);
        final int camp_length = 3;
        
        int start = in.nextInt();
        int end = in.nextInt();
        List<Integer> trip = new ArrayList<>();
        
        // 旅行の日程
        for(int i=start; i<=end; i++){
            trip.add(i);
        }
        
        // 日程重複の確認
        int count = 0;
        int N = (camp_length > trip.size()) ? trip.size() : camp_length;

        for(int a : trip){
            if(camp.contains(a)){
                count++;
            }                
        }
        System.out.println(camp_length - count);
        
    }
}