Draw the state-transition diagram for an elevator controller using the considerations listed below. Note that you do not need to draw a circuit or write a VHDL program to implement the state machine; just draw the state-transition diagram. The elevator services four floors, which are named following the United Kingdom floor naming style; from top to bottom we have third floor, second floor, first floor, ground floor. Each state of the finite state machine is labelled for the floor corresponding to the state, e.g. ground floor corresponds with state number 0. There are two inputs, up and down. If neither input or both intpus are high, the elevator stays on its current floor. If the up input is high and the down input is low, the elevator transitions one floor up, if possible. If an upward transition is not possible, no transition is made. If the up input is low and the down input is high, the elevator transitions one floor down, if possible. If a downward transition is not possible, no transition is made.