two years
1 Kings 15:25
And Nadab the son of Jeroboam began to reign over Israel in the second year of Asa king of Judah, and reigned over Israel two years.
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2 Kings 1:17
So he died according to the word of the LORD which Elijah had spoken. And Jehoram reigned in his stead in the second year of Jehoram the son of Jehoshaphat king of Judah; because he had no son.
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