In what year did John F. Kennedy first take office as President?

Who succeeded John F. Kennedy as President of the United States? Who was President immediately before John F. Kennedy? Which political party did President John F. Kennedy belong to? Which president served from 1961 to 1963? Under which president did Lyndon B. Johnson serve as Vice President? Who was First Lady during John F. Kennedy's presidency? Jacqueline Kennedy was married to which president? Which number president was Lyndon B. Johnson?