You enter the building where the customer is located to deliver a pizza order. You need to reach the 12th floor, but there's a problem. The only way to go up is to understand how the system works.

You need to check whether there is anything unusual on each floor.

The only way to move between floors is by elevator. However, the elevator has no floor buttons—only Up and Down buttons. You get into the elevator and press the Up button, arriving at the 1st floor. But after that, when you press the Up button again, there is a chance that you won't move to the next floor. The building has trapped you in a loop.

Your task is to look for any differences or anomalies on the floor you are currently on. If you find a difference, get into the elevator and press the Down button to advance to the next floor. If there is no difference, get into the elevator and press the Up button to advance to the next floor.

This is the core mechanic of the game.

Starting from the entrance floor, your goal is to successfully reach the 12th floor and deliver the pizza order.