The number of individuals in deme C remained at 246 until 636.6647 generations ago, at which time it increased to a new stable size of 3984.
time_units: generations
demes:
  - name: C
    start_time: .inf
    epochs:
      - start_size: 246
        end_time: 636.6647
      - start_size: 3984
        end_time: 0