def get_median_watch_time(event):
    """Computes the median watch time based on LA1-provided mapping from
    watch times to number of unique viewers.
    NOTE: This data is only available at 5 minute granularities."""
    times = []
    for m, v in event['geodata']['watchTimes'].items():
        times += [int(m)] * v
    return times[len(times) // 2]