How can I exclude a team from a selector?

I am making a Minecraft map and I made a minigame. I have this automatic effect to give infinite regeneration. I want to exclude the people playing the game from regeneration.

The command I had is

effect give @a Minecraft:regeneration 10 255 true

Solution 1:

Although it took a long time i finally figured it out. The exclamation mark (!) character is used for not. So, the command is:

effect @a[team=!team1] minecraft:regeneration 10 255 true