t = gets.to_i
n = gets.to_i
$c_list = gets.split.map(&:to_i)
$v_list = gets.split.map(&:to_i)

$max_manzoku = 0

def manzoku(kore)
  man = 0
  kore.each_with_index do |count, i|
    m = $v_list[i]
    count.times do
      man += m
      m /= 2
    end
  end
  return man
end

def noru_ato(nokori, ima, kore)
  if ima == n - 1
    kore << nokori / $c_list[ima]
    $max_manzoku = [manzoku(kore), $max_manzoku].max
  else
    count = 0
    loop do
      next_nokori = nokori - count * $c_list[ima]
      if next_nokori <= 0
        noru_ato(next_nokori, ima + 1, kore + [count])
        count += 1
      else
        break
      end
    end
  end
end

noru_ato(t, 0, [])

puts $max_manzoku