This nation's national anthem, among the longest in the world, consists of two stanzas of 26 lines each. By law, when played only by musicians, the second stanza may be omitted, but when sung, both stanzas must be sung in their entirety. Identify this nation with an anthem which opens with the lines (in a rough English translation):
The placid banks of the Ipiranga heard
The resounding cry of a heroic folk
And the sun of Liberty in shining beams
Shone in the homeland's sky at that instant.