You have heard many times during the week on the radio that there is a bloodthirsty maniac in the city who has killed 45 people and cannot be caught. For you this is absurd and you do not believe in this nonsense. Now it’s summer and you often need clean air, so you went out for a walk, as expected, there was no one on the street, because everyone is afraid of this maniac. But then you hear that someone is following you, but everything is fine for you.