class MyQueue {

private Stack<Integer> stack1 = new Stack<Integer>();

private Stack<Integer> stack2 = new Stack<Integer>();

// Push element x to the back of queue.

public void push(int x) {

stack1.push(x);

}

// Removes the element from in front of queue.

public void pop() {

pushFromStack1ToStack2();

stack2.pop();

}

// Get the front element.

public int peek() {

pushFromStack1ToStack2();

return stack2.peek();

}

// Return whether the queue is empty.

public boolean empty() {

return stack1.empty() && stack2.empty();

}

private void pushFromStack1ToStack2() {

if (stack2.empty()) {

while (!stack1.empty()) {

stack2.push(stack1.pop());

}

}

}

}