How many US tourists have to go to Cuba to compensate the loss of Venezuelan oil?

How many US tourists have to go to Cuba to compensate the loss of Venezuelan oil?

 

 Source: Cuba Is Hoping To Replace Venezuelan Oil With American Tourists | FiveThirtyEight - http://fivethirtyeight.com/features/cuba-is-hoping-to-replace-venezuelan-oil-with-american-tourists/