Read this: Praca dos Tres Poderes (Portuguese for Square of the Three Powers) is a plaza in Brasilia. The name is derived from the encounter of the three federal branches around the plaza: the Executive, represented by the Palacio do Planalto (presidential office); the Legislative, represented by the National Congress (Congresso Nacional); and the Judicial branch, represented by the Supreme Federal Court (Supremo Tribunal Federal). It is a tourist attraction in Brasilia, designed by Lucio Costa and Oscar Niemeyer as a place where the three branches would meet harmoniously.

What is the presidential office designed by Lucio Costa and Oscar Niemeyer called?
What is the answer? (If it cannot be answered, return "unanswerable")
unanswerable