The challenges change depending on the song. There are some songs where the lyrics are really a challenge and then there are other songs where the lyrics are there and the music is a challenge. And then you've got rock songs where the challenge is the tightness of the arrangement with the band. The music and the lyrics are there, but it's a challenge to get the arrangement correct. So I wouldn't be able to point to one thing. What the challenge is changes all of the time.