class MinStack {

	Node stack;
	int size;

	public void push(int data) {
		if (size == Integer.MAX_VALUE)
			throw new StackOverflowError();
		Node node = new Node(data);
		int min = Integer.MAX_VALUE;
		if (stack != null && stack.min != null)
			min = stack.min.data;
		if (data <= min)
			node.min = node;
		else
			node.min = stack.min;
		node.next = stack;
		stack = node;
		size++;
	}

	public void pop() {
		if (stack == null)
			throw new EmptyStackException();
		stack = stack.next;
		size--;
	}

	public int top() {
		if (stack == null)
			throw new EmptyStackException();
		return stack.data;
	}

	public int getMin() {
		if (stack == null)
			throw new EmptyStackException();
		if (stack.min == null)
		    return 0;
		return stack.min.data;
	}

	class Node {

		int data;
		Node next;
		Node min;

		public Node(int data) {
			this.data = data;
		}
	}
}