Given a spy and a handler, they communicate as follows: each day, the spy walk across a building which has 100 windows, and he can choose which window to break. The handler goes to look at the building each night. The question is how many bit of info can be transmitted. The second part is the following variant: each night the handler can now repair windows. The task is to come up with a scheme that maximize the minimum possible amount of bits of info transmitted every night.