Which president is counted as both the 22nd and the 24th President?

Who was the 42nd President of the United States? Who was the 43rd President of the United States? Who was the 44th President of the United States? Who was the 46th President of the United States? Which president is counted as both the 45th and the 47th President? Which two presidents served non-consecutive terms? Which president served the longest, being elected four times? Which constitutional amendment, ratified in 1951, limits presidents to two elected terms?