Until 6613.1 generations ago, the population of deme C was 460. At that point, it increased to 4895, where it has stayed up to now.
time_units: generations
demes:
  - name: C
    start_time: .inf
    epochs:
      - start_size: 460
        end_time: 6613.1
      - start_size: 4895
        end_time: 0