import Calendar.Day;


class P07_ShortCircuit_DayChk {
	
	public static void main(String[] args)
	{
		Day day=null;
		
		int y,m,d;
		y=2014; m=13; d=31; 
		
		if (Day.valid(y, m, d))
			day= new Day(y,m,d);
		
		if (day.isEndOfAMonth()) 
			System.out.println("end of month");
		
		System.out.println("program stops here");
	}
}

//if (day!=null&&day.isEndOfAMonth()) //avoid runtime error: java.lang.NullPointerException