```java
ublic static int numberOfLeapYears(int year1, int year2) {
      int counter = 0;
      for (int i = year1; i <= year2; i++)
         if (isLeapYear(i))
            counter++;
      return counter;
   }
   public static int dayOfWeek(int month, int day, int year) {
      return (dayOfYear(month, day, year) + firstDayOfYear(year) - 1) % 7;
   }
public class StepTracker {
   private int activeThreshold;
   private int totalSteps;
   private int days;
   private int activeDays;

   public StepTracker(int activeThreshold) {
      this.activeThreshold = activeThreshold;
      totalSteps = 0;
      days = 0;
      activeDays = 0;
   }
   public void addDailySteps(int steps) {
      days++;
      totalSteps += steps;
      if (steps >= activeThreshold)
         activeDays++;
   }
   public int activeDays() {
      return activeDays;
   }
   public double averageSteps() {
      return (double) totalSteps / days;
   }
}
```