Originally, deme B had a population size of 1180, which grew to 8950 around 4425.4 generations ago and has not changed since.
time_units: generations
demes:
  - name: B
    start_time: .inf
    epochs:
      - start_size: 1180
        end_time: 4425.4
      - start_size: 8950
        end_time: 0