Recently, wyh had learned a lot of knowledge about attack others’ computers. Now, if he has a way to access someone’s computer, the computers those connected directly or indirectly will suddenly be broken. To avoid it happening, the government set several computers with “Security Center”. These computers can prevent wyh’s attack. So they are called anti-wyhs. What’s more, anti-wyhs can protect the computers those connect to them directly or indirectly from wyh’s dreadful attack. But anti-wyhs can’t connect to a computer indirectly through wyh’s computer.
Now, the government asks you how many computers have been attacked.