I recently was attempting to upload a beatmap for a song from Cytus II/DJMAX. The upload failed, saying that the audio was previously removed by the copyright holder. I am aware of this thing called "fair use" in the US (fair dealing elsewhere) which allows for the transformative use of copyrighted material without explicit permission for the copyright holder. What should I do? Ask the copyright holder for permission? Map a different song? Wait for the song to be licensed for osu!? All three of the above? And since when did osu! have content ID?