gets                                                                                                                                                          
arr = gets.chomp.split.map(&:to_i)                                                                                                                            
if arr.size % 2 == 0                                                                                                                                          
  p (arr.sort[arr.size/2-1] + arr.sort[arr.size/2]).to_f / 2                                                                                                  
else                                                                                                                                                          
  p arr.sort[arr.size/2].to_f                                                                                                                                 
end