class MinStack {

private Stack<int[]> st = null;

public MinStack() {

st = new Stack<>();

}

public void push(int val) {

if(!st.isEmpty()){

int[] top = st.peek();

int min = Math.min(top[1], val);

st.push(new int[]{val, min});

} else {

st.push(new int[]{val, val});

}

}

public void pop() {

if(!st.isEmpty()) {

st.pop();

}

}

public int top() {

int[] top = st.peek();

return top[0];

}

public int getMin() {

int[] top = st.peek();

return top[1];

}

}

/**

* Your MinStack object will be instantiated and called as such:

* MinStack obj = new MinStack();

* obj.push(val);

* obj.pop();

* int param_3 = obj.top();

* int param_4 = obj.getMin();

*/