n = gets.chomp!.to_i
a = Array.new(n)
b = gets.chomp!.split(' ').map(&:to_i)
a= b.dup

a.sort!
if a.length.odd?
  puts a[a.length / 2]
else
  puts sprintf('%.1f', (a[a.length / 2 - 1] + a[a.length / 2]) / 2.0)
end