How long would it take to walk across the wall?

The wall is as long as 13,170.69 miles. And some sections have become ruins. So it will take very long time to hike on the wall. According to what I read, there was a foreigner who spent around 6 months to explore the Ming Dynasty Wall from Shanhaiguan Pass to Jiayuguan Pass. If he walked day and night, I think he would saved at least 3 months. But it's impossible unless he was ironman.