题目内容：

英语翻译
The highest building in our city has only one elevator.A request list
is made up with N positive numbers.The numbers denote at which floors
the elevator will stop,in specified order.It costs 6 seconds to move
the elevator up one floor,and 4 seconds to move down one floor.The
elevator will stay for 5 seconds at each stop.
For a given
request list,you are to compute the total time spent to fulfill the
requests on the list.The elevator is on the 0th floor at the beginning
and does not have to return to the ground floor when the requests are
fulfilled.