Lol. The irony is delicious. Largest is size, populous is population.

"On two occasions I have been asked, 'Pray, Mr. Babbage, if you put into the machine wrong figures, will the right answers come out?' I am not able rightly to apprehend the kind of confusion of ideas that could provoke such a question." "

How did you manage to get this wrong?

From google, the total area of South American countries:

1. Brazil: 3,287,957 sq miles

2. Argentina: 1,073,518 sq miles

3. Peru: 496,225 sq miles