class MinStack {

    Stack<Integer> stack = new Stack<>();
    Stack<Integer> minStack = new Stack<>();

    public void push(int x) {
        stack.push(x);
        if(minStack.isEmpty()){
            minStack.push(x);
            return;
        }
        if(minStack.peek() > x){
            minStack.push(x);
            return;
        }else{
            minStack.push(minStack.peek());
            return;
        }
    }

    public void pop() {
        if(!stack.isEmpty()){
            stack.pop();
            minStack.pop();
        }
    }

    public int top() {
        if(!stack.isEmpty()){
            return stack.peek();
        }else{
            return -1;
        }

    }

    public int getMin() {
        if(!minStack.isEmpty()){
            return minStack.peek();
        }else{
            return -1;
        }
    }
}