class Program
{
    private void Beep(int frequency)
    {
        Console.Beep(frequency, 100);
    }

    private void PlayMelody(string melody, int timeout)
    {
        for (int i = 0; i < melody.Length; i++)
        {
            var freq = Enum.Parse<Frequencies>(melody[i].ToString());

            Beep((int)freq);
            Thread.Sleep(1000);
        }
    }

    public Task PlayMelodyAsync(string melody, int timeout) => Task.Run(() => PlayMelody(melody, timeout));
}