Ranked choice voting

A ranked-choice voting system (RCV) is an electoral system in which voters rank candidates by preference on their ballots. If a candidate wins a majority of first-preference votes, he or she is declared the winner. If no candidate wins a majority of first-preference votes, the candidate with the fewest first-preference votes is eliminated. First-preference votes cast for the failed candidate are eliminated, lifting the second-preference choices indicated on those ballots. A new tally is conducted to determine whether any candidate has won a majority of the adjusted votes. The process is repeated until a candidate wins an outright majority. This system is sometimes referred to as an instant runoff voting system.

https://ballotpedia.org/Ranked-choice_voting_(RCV)