$4.$ How would you modify the FSM from the last problem so that it would create the behavior of a cellphone power$-$down procedure; specifically, to turn the phone off, you must hold the power button down for exactly one clock cycle after which pressing the button again $(\backslash ($ b$=1\backslash ))$ would turn the phone back on$?$ Sketch the modified $3-$state state diagram that achieves this behavior and describe its behavior in a sentence or two. $(20$ points$)$