n, m = gets.chomp.split(' ').map(&:to_i)
a = gets.chomp.split(' ').map(&:to_i).sort
raise 'NO' unless n == a.size

m.times do
  tmp = a.pop
  tmp = tmp.to_f / 2
  index = a.bsearch_index {|x| x >= tmp} || a.size
  a.insert(index, tmp)
end
sum = 0
a.each do |point|
  sum += point.to_i
end
puts sum