长整除
public class LongDivision{
public static void main(String[] args){
final long MICROS_PER_DAY = 24*60*60*1000*1000;
final long MILLIS_PER_DAY = 24*60*60*1000;
System.out.println(MICROS_PER_DAY/MILLIS_PER_DAY);
}
}