def countdown(t):
    while t:
        menit,detik = divmod(t,60)
        jam,menit = divmod(menit,60)
        jam = str(jam).zfill(2)
        menit = str(menit).zfill(2)
        detik = str(menit).zfill(2)
        print(f'waiting until {jam}:{menit}:{detik} ',flush=True,end='\r')
        t -= 1
        time.sleep(1)
    print('                          ',flush=True,end='\r')