the president does both
President pro tempore of the Senate becomes President.
President of the Senate and to be ready to serve as president in the event that the president becomes incapacitated or dies.
The President pro tempore of the Senate becomes the President. He/she is the leader of the Senate when the vice president can not attend. If him/her dies also then the Secretary of State becomes President.
If the President dies, the Vice-President takes the Presidential Oath of Office and becomes President of the United States. She then appoints a new Vice-President, with the advice and consent of the Senate.
The next person in the order of succession after the Vice-President is the Speaker of the House, then the Senate's President Pro Temp, and then the Secretary of State.
If he dies in office, then Dick Cheney becomes President.
The vice president
The Vice President
The vice-president
the vice president.
If both die then the Speaker of the House becomes president
The vice-president becomes the president.