* The six candidates approved for Iran's strictly vetted presidential ballot are appearing for the last of three live televised debates before the May 19 election. The topic is economics.

* Iranian President Hassan Rohani is seeking a second four-year term. His main challenges from the conservative side are expected to come from cleric Ebrahim Raisi and Tehran Mayor Mohammad Baqer Qalibaf. (Read profiles of the candidates.)

* The official campaign period ends on May 17, two days before voting in the first round of a possible two-round election. If no candidate gets more than half of the vote, the second round would be held on May 26.

* Official media put the number of eligible voters at around 55 million.

* In the first debate, the candidates clashed over Rohani's record on job creation. In the second debate, Rohani's conservative rivals accused him of having failed to "cash the check" from the 2015 deal curbing Tehran's nuclear program in exchange for international sanctions relief.

*NOTE: Times are stated according to local time in Tehran (GMT +4 1/2)