How long to walk the great wall of China

It is said that the great wall is about 5,500 miles (8,851 km) long. If you walk 15 miles (25 km) per day, it is roughly estimated that you need one year to cover them all.

Well, I had heard the news that several Singapore monks finished the way in 9 months.

Wrong. That is just the Beijing portion. The total length of the Great Wall is actually 13,170 Miles

How long is the Ming Great Wall? - 8,851.8 km (5,500.3 mi)
The Ming Great Wall is the best-preserved among all, extending from Hushan in Liaoning to Jiayuguan in Gansu. It includes 6,259.6-kilometer (3,889.5-mile) artificial wall, 359.7-kilometer (223.5-mile) trench and 2,232.5-kilometer (1,387.2-mile) natural barrier. It is composed of 5,723 beacon towers, 7,062 watching towers, 3,357 wall platforms and 1,026 other related ruins. The Great Wall sections in Beijing are mainly left by the Ming Dynasty.

If you walk all the great wall's it takes 175 days.

Then what is there opposite of Beijing wall, was it the area of Mongolians historically?