The building consists of the 'n' number of floors, where n is a random number generated at program start in the range 5 <= n <= 20. There are 'k' number of passengers on each floor, where k is a random number generated at program start in the range 0 <= k <= 10. Each passenger wants to arrive at a certain floor different from the one on which he is. Each floor has two buttons to call the elevator "Up" and "Down". exception make up the lower and upper floors. The elevator has a capacity limit of 5 people maximum.