President Donald Trump has narrowed the search for his third White House chief of staff to five “mostly well known” people, he told reporters Thursday.

“We are interviewing people now for chief of staff,” the president said five days after he announced John Kelly would leave the post at the end of the year. Nick Ayers, Vice President Mike Pence’s chief of staff, turned him down Sunday and is leaving the White House to leave Washington and work for a pro-Trump political action group.

Trump said his five candidates are “really good ones” and “terrific people.”

Some GOP sources, however, doubt any of the candidates can effectively manage Trump.

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The president, before he was even a candidate for the job, once criticized then-President Barack Obama for having multiple chiefs of staff in three years. But he soon will have had three in just two years in office.

“3 Chief of Staffs in less than 3 years of being President: Part of the reason why @BarackObama can’t manage to pass his agenda,” businessman and reality television host Trump tweeted in January 2012.

3 Chief of Staffs in less than 3 years of being President: Part of the reason why @BarackObama can’t manage to pass his agenda.

— Donald J. Trump (@realDonaldTrump) January 10, 2012