The new rock sensation U3 is having a concert at Video City Music Hall. The orchestra section holds 4,730 people. The mezzanine section holds 6,713 people, while the balcony holds 8,444 people. The section behind the stage holds 10, 472 people. In all, 23,646 fans attended the concert. They filled three whole sections. Which section of Video City Music Hall was empty for the concert?