Intellectual problems should also conform to the basic law. You're asking an embarrassing question. Different water? Mineral water and salt water? There are three more cups? It's also very tangled, all of which are brain teasers, but then again, the same amount is equal, that is, 0=0=0. As long as all three glasses of water are poured out, the water in the three cups is the same.

The best answer is that you can wash and sleep.