23:49 Now I understand why the Chinese community places great emphasis on their children learning to play musical instruments, especially the piano. one example, if we couldn't look for a job or our salary is not commensurate. we can play the piano and upload videos to youtube, where we can generate side income. or just go to the street every weekends and play street music and from there we can find friends and explore the world. i regret not learning any music instrument. but i'll start now. guitar catch my interest.