John, the Mentor

When John, the Mentor enters the battlefield
choose a creature type.
All creatures of the chosen type you control get
+1/+1.
{1}{g}: Creatures you control of the chosen type
gain trample until end of turn.
{1}{w}: Creatures you control of the chosen type
gain +1/+1 until end of turn.
{1}{u}: Creatures you control of the chosen type
gain flying until end of turn.