bns

class MyStack
{
    private int size = 0;
    private ArrayList list;

    public MyStack()
    {
        list = new ArrayList();
    }
    public void push(Object o)
    {
        list.add(size,o);
        size++;
    }
    public int search(Object o)
    {
        if(!list.isEmpty())
        {
            if(list.contains(o))
                return list.lastIndexOf(o);
            else
                return -1;
        }
        return -1;
    }
    public Object pop()
    {
        if(!list.isEmpty())
        {
            size--;
            Object ob = list.size() - 1;
            list.remove(list.size()-1);
            return ob;
        }
        return -1;
    }
    public Object peek()
    {
        if(!list.isEmpty())
        {
            return list.get(list.size()-1);
        }
        return -1;
    }
    public int getSize()
    {
        return size;
    }
    public Boolean isEmpty()
    {
        return size == 0 ? true:false;
    }
    public String toString()
    {
        String s = new String();
        for(int i = 0 ;i < size;i++)
        {
            s += list.get(i).toString() + " ";
        }
    }
}