No Vice-President shall serve for more than two successive terms. Voluntary renunciation of the office for any length of time shall not be considered as an interruption in the continuity of the service for the full term for which he was elected. Unless otherwise provided by law, the regular election for President and Vice-President shall be held on the second Monday of May. The returns of every election for President and Vice-President, duly certified by the board of canvassers of each province or city, shall be transmitted to the Congress, directed to the President of the Senate. Upon receipt of the certificates of canvass, the President of the Senate shall, not later than thirty days after the day of the election, open all the certificates in the presence of the Senate and the House of Representatives in joint public session, and the Congress, upon determination of the authenticity and due execution thereof in the manner provided by law, canvass the votes. The person having the highest number of votes shall be proclaimed elected, but in case two or more shall have an equal and highest number of votes, one of them shall forthwith be chosen by the vote of a majority of all the Members of both Houses of the Congress, voting separately. The Congress shall promulgate its rules for the canvassing of the certificates. The Supreme Court, sitting en banc, shall be the sole judge of all contests relating to the election, returns, and qualifications of the President or Vice-President, and may promulgate its rules for the purpose. Section 5. Before they enter on the execution of their office, the President, the VicePresident, or the Acting President shall take the following oath or affirmation: "I do solemnly swear [or affirm] that I will faithfully and conscientiously fulfill my duties as President [or Vice-President or Acting President] of the Philippines, preserve and defend its Constitution, execute its laws, do justice to every man, and consecrate myself to the service of the Nation. So help me God." [In case of affirmation, last sentence will be omitted]. Section 6. The President shall have an official residence. The salaries of the President and Vice-President shall be determined by law and shall not be decreased during their tenure. No increase in said compensation shall take effect until after the expiration of the term of the incumbent during which such increase was approved. They shall not receive during their tenure any other emolument from the Government or any other source. Section 7. The President-elect and the Vice President-elect shall assume office at the beginning of their terms. If the President-elect fails to qualify, the Vice President-elect shall act as President until the President-elect shall have qualified.