import java.util.Scanner;

public class No773
{
	public static void main(String args[])
	{
		Scanner sc = new Scanner(System.in);
		int saisyo = sc.nextInt();
		int saigo = sc.nextInt();

		int ikeru = 3;
		for( int i = saisyo; i <= saigo; i++ )
		{ if( i == 23 || i == 24 || i == 25 ){ ikeru -= 1; } }

		System.out.println( ikeru );
	}
}