private static int whoWon(char user1, char user2) throws Exception {
        if (user1 == user2) {
            return 0;
        } else if ((user1 == 'r' && user2 == 's') || (user1 == 's' && user2 == 'p') || (user1 == 'p' && user2 == 'r')) {
            return 1;
        } else if (whoWon(user2, user1) == 1) { // just to idiot check
            return -1;
        } else {
            throw new Exception("Invalid choice for one of the users! u1:" + user1 + " u2:" + user2);
        }
    }