At least two +1/+1 counters on Marath, Will of the Wild.
Steps
Activate Marath, Will of the Wild's ability by paying ({1} magic symbol) and removing one +1/+1 counter from it, creating a 1/1 Elemental creature token.
Ivy Lane Denizen triggers, causing you to put a +1/+1 counter on Marath.
Activate Ashnod's Altar by sacrificing an Elemental token, adding ({C} magic symbol) ({C} magic symbol) .