Player 1 puts up an amount of fingers (not 0). This will be added to the total. Then player 2 will do the same thing, and so on. The total has to be prime, otherwise the opposing player wins. For example: Player one puts 2 fingers up. The total is 2. Player two puts 5 fingers up. The total is 7. Player one puts 3 fingers up. The total is 10. Since the total is not prime, player two wins.
Thanks to @montion183 for actually doing all the hard work coding, I just changed the aesthetics to a very dreamy vibe. Um, comment if you wanna change anything? I did this because (no offense) the other one was kinda ugly even though the game was fun, so I made it more nice! So now we have a great game and gameplay.