WWZ

Let’s take you to one of the spectacular movie scenes from the famous Brad Pitt movie, [World War Z](https://en.wikipedia.org/wiki/World_War_Z_(film)). We’re talking about the scene where the Mossad set up a safe zone in Movie world Jerusalem, before the zombie outbreak. The city is in the form of an $M$ x $N$ binary grid and has massive Border Walls protecting it from the zombies outside. Howeve