a, b = gets.split.map(&:to_i)

if a < 3 || a > 20 || b < 3 || b > 20
  puts "invalid argunment: 3 <= a, b <= 20"
  exit 0
end

res = 0
2.times do
  if a > b
    res += a
    a -= 1
  else
    res += b
    b -= 1
  end
end
puts res
