Voters in each constituency elect three pairs, each consisting of a titular representative and his or her substitute.
The election is held by secret, single-member, multi-mandate majority ballot.
Each elector may vote for a maximum of three different pairs of candidates (full and alternate). Any vote involving more than three pairs of candidates or more than one vote for the same pair of candidates shall be null and void.
The three pairs of candidates who win the election are those who have the most votes.
The three pairs of candidates with the highest number of votes are elected.
In the event of a tie, the candidate with the highest number of votes is elected.
In the event of a tie, the election is won by the incumbent candidate with the greatest number of years in office or, in the event of equal seniority, by the oldest incumbent candidate.