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

max_cookie = 1
for i in 1..k do
  cookie = 1
  # i回だけ割る
  cookie += i

  # 交換不可
  next if cookie < a

  # 操作回数が奇数
  next if (k - i) % 2 > 0

  if b > a
    change = (k - i) / 2
    cookie += (b - a) * change
  end
  if max_cookie > cookie
    break
  else
    max_cookie = cookie
  end
end

print("#{max_cookie}\n")