Using a timer, design a system with single-bit inputs U and D corresponding to two buttons, and a 16-bit output Q which is initially 0. Pressing the button for U causes Q to increment, while D causes a decrement; pressing both buttons causes Q to stay the same. If a single button is held down, Q should then continue to increment or decrement at a rate of once per second as long as the button is held. Assume the buttons are already dcbounccd. Assume Q simply rolls over if its upper or lower value is reached.