class MinStack {

	private static Node max = new Node(Integer.MAX_VALUE);
	private Node stack;

	public MinStack() {
		stack = new Node(Integer.MAX_VALUE);
		stack.min = max;
	}

	public void push(int data) {
		Node node = new Node(data);
		node.next = stack;
		if (data <= stack.min.data)
			node.min = node;
		else
			node.min = stack.min;
		stack = node;
	}

	public void pop() {
		stack = stack.next;
	}

	public int top() {
		return stack.data;
	}

	public int getMin() {
		return stack.min.data;
	}
}

class Node {

	public int data;
	public Node min;
	public Node next;

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