Decree of Growth

Creatures you control enter the battlefield with a
+1/+1 counter.
At the beginning of your upkeep, choose target creature with three or more counters on it. You
may exile it. If you do, you gain life equal to that creature's power and create a number of 1/1
green saproling creature tokens equal to its
power. Then place a +1/+1 counter on target creature.
What is the end of the cycle?