Englishman, a Scotsman and a Chinese man

There-s an Englishman, a Scotsman and a Chinese man. The Englishman says ""I bet my dog can run round the park 50 times without needing a wee. After 40 times it had a wee."" Then the Scotsman said ""I bet my dog can run round the park 100 times without needing a wee."" After 90 times, the dog had a wee. Then the Chinese man said ""I bet my dog can run round the park 200 times without needing a wee."" It got round 200 times without needing a wee. The Englishmen and Scotsman said to the Chinese man ""How did it do that?"" The Chinese man said ""Me not stupid, me not silly, me tie knot in my dogs wiily""