public class BoundedBag
{
  private int[] element;
  private int[] counter;
  private int number = 0;
  private int sum = 0;
  
  public BoundedBag(int n)
  {
    element = new int[n];
    counter = new int[n];
    number = 0;
    sum = 0;
  }

  public int size()
  {
    return element.length;
  }

  public int elements()
  {
    return number;
  }
  
  public int instances()
  {
    return sum;
  }

  public void add(int e, int n)
  {
    if (n == 0) return;
    sum += n ;
    int i = find(e);
    if (i != -1)
    {
      counter[i] += n;
      return;
    }
    element[number] = e;
    counter[number] = n;
    number++;
  }

  public void remove(int e, int n) 
  {
    int i = find(e);
    if (i == -1) return;
    if (counter[i] > n)
    {
      counter[i] -= n;
      sum -= n;
      return;
    }
    number--;
    sum -= counter[i];
    element[i] = element[number];
    counter[i] = counter[number];
  }

  private int find(int e) 
  { 
    for (int i=0; i<number; i++)
    {
      if (element[i] == e) return i;
    }
    return -1;
  }
}