You are playing an online RPG game with 9 friends of yours (10 people in total) and in the game, there is a 2-player dungeon where you level up every time you enter and complete it. Only up to two players are allowed inside it at a time. At the beginning of the game, everybody is level 1 as usual. Before the game released, there was a beta and you know how to level up fast from it, but there are some tricks you discovered.
- You cannot complete the dungeon alone.
- After completing this 2-player dungeon with your friend, you and your friend will get 1 level.
- If you play the dungeon with someone exactly one level below you, you will get an extra item at the end of the dungeon, but you cannot enter the dungeon with a friend more than one level below you.
- If you try to enter the dungeon with the same person again, no one will get any experience to level up or item.
- You can share the items later, they are not soulbound (Meaning, they can only ever belong to the player who obtained them)!
What is the maximum number of extra items you will get in total as a group from this dungeon?