Fifty-six primary contests were conducted to choose 2,472 delegates. In 50 states and territories the delegates were allocated to candidates by popular vote either statewide or on the congressional district level and then elected according to state rules. In six states and territories, the first-instance popular vote did not allocate any delegates; they were elected later at local conventions and either bound to a candidate or uncommitted. Most delegates were elected as bound delegates, meaning that they were required to vote for a specific candidate on the first ballot at the national convention. Some delegates attended the convention as unbound or uncommitted delegates, meaning that they were free to vote for anyone at the first ballot. These 130 uncommitted delegates included 18 unbound RNC delegates and 112 delegates that have been elected or allocated as uncommitted. Uncommitted delegates were still at liberty to express a preference for a candidate, although that preference was not binding. Among the 901 delegates elected for candidates who later dropped out of the race, 155 were still bound to vote for their candidate on the first ballot and 34 were released according to the local rules of each state party. If no candidate were elected in the first round of voting, a progressively larger number of delegates would have been allowed to vote for the candidate of their choice. The voting rules on subsequent ballots were determined by individual states: most states released their delegates on the second round of voting, and only four states kept them bound on the third round and beyond.