Stack that Support Push, Pop, and GetMin in Constant Time

ConstantStackMinimum.java

/*
Design a stack that supports push, pop, and retrieving the minimum element in constant time. Can you do this?
Solution:

Keep a stack of minimums: Extra memory

*/


public class StackWithMin{

private Stack<Integer> normalstk=new Stack<Integer>();
private Stack<Integer> minstk=new Stack<Integer>();
// while pushing into 
//Push into minstk if inserted element is smaller than smallest input element or if minstk is empty
//
public void push(int input)
{
  if(minstk.isEmpty()|| (x<minstk.top() )
    minstk.push(input);
  //push into normal stk anyways
  normalstk.push(input);
}

//while popping if element is =minstk.top then pop from minstk too
public int pop()
{
  if normalstk.isEmpty()
    return -1; //stk is empty
  int ret=normalstk.pop();
  if(ret==minstk.top())
    minstk.pop();//pop from minstk as well!
  return ret;
}


//get the minimum at any point
public int getMin()
{
  if(minstk.isEmpty())
    return -1;
  return minstk.pop();
}

}

I think if(minstk.isEmpty()|| (x<minstk.top() ) needs to be if(minstk.isEmpty()|| (x<=minstk.top() ), What do you think?

following test case fails:

["push","push","push","getMin","pop","getMin"]
[[0],[1],[0],[],[],[]]