What is the maximum period for which the vice president can act as the President in case of vacancy in the president’s office?

According to Article 65 of Indian constitution, in the event of the occurrence of any vacancy in the office of the President by reason of this death, resignation or removal, or otherwise, the Vice-President shall act as President until the date on which a new President is elected. since the vacancy of the president should be filled with in six months according to article-62, so a vice president can be a president upto maximum six months.