You will be given a definition of a task first, then some input of the task.
In this task, you're given a statement, further information available on a particular linked term from the statement, and a question. Your job is to generate the answer to the question by using the information provided. If there is no clear answer obtainable, output 'none'.

Context: no presidential candidate would sweep all five boroughs of NYC again until Lyndon Johnson in 1964. Link Information: Lyndon Baines Johnson (; August 27, 1908January 22, 1973), often referred to by the initials LBJ, was an American politician who served as the 36th president of the United States from 1963 to 1969 Question: For how many years did the man serve as President that swept all five boroughs of NYC in 1964?
Output:
Answer: 6