public class AppointmentBookRunner
{
    public static void main(String[] args) 
    {
        AppointmentBook x = new AppointmentBook();
	x.reserveBlock(2, 0, 10);
	x.reserveBlock(2, 15, 15);
	x.reserveBlock(2, 45, 10);

	System.out.println( x.findFreeBlock(2, 5);
	System.out.println( x.findFreeBlock(2, 15));
	System.out.println( x.findFreeBlock(2, 9));
	System.out.println( x.findFreeBlock(2, 20));
    }
}