[
    new MagicWhenOtherComesIntoPlayTrigger() {
        @Override
        public MagicEvent executeTrigger(final MagicGame game,final MagicPermanent permanent,final MagicPermanent otherPermanent) {
            return (otherPermanent.isFriend(permanent) &&
                    otherPermanent.hasSubType(MagicSubType.Ally)) ?
                new MagicEvent(
                    permanent,
                    new MagicSimpleMayChoice(
                        MagicSimpleMayChoice.GAIN_LIFE,
                        1,
                        MagicSimpleMayChoice.DEFAULT_YES
                    ),
                    this,
                    "PN may\$ gain life equal to " +
                    "the number of Allies he or she controls."
                ) :
                MagicEvent.NONE;
        }

        @Override
        public void executeEvent(final MagicGame game, final MagicEvent event) {
            if (event.isYes()) {
                final MagicPlayer player = event.getPlayer();
                final int amount =  player.getNrOfPermanents(MagicSubType.Ally);
                if (amount > 0) {
                    game.doAction(new MagicChangeLifeAction(player,amount));
                }
            }
        }
    }
]