When 6 minutes left, ESPN TV said that there are 40 lead changes. That's why I thought the lead change is close to 50. But I just read the report, the lead changes are only 23 times.
“The lead changed hands 23 times. There were 14 ties.”
http://www.si.com/college-basketball/2017/03/05/north-carolina-duke-acc-joel-berry-grayson-allen#