Two of them....
One will be for believers.
The other is for unbelievers.
One will be for removing Christians, which will take place just before the seven-year Tribulation.
For that reason the Tribulation will begin with all unbelievers.
The second one will be for removing all unbelievers just before the Millennium begins.
That is how the Millennium will begin with all believers.
The rapture of unbelievers before the Millennium takes place:
For as in the days before the flood, they were eating and drinking, marrying and giving in marriage,
until the day Noah entered into the ark. And they did not know anything until the deluge came and
swept them all away. So also will be the coming of the Son of Man. Then there will be two men in the
field; one will be taken and one left. Two women will be grinding at the mill; one will be taken and one
left. Therefore, be on the alert, because you do not know what day your Lord is coming!
Matthew 24:38-42