Originally, deme B had a population size of 8201, which changed to 1526 around 4304.0 generations ago and has not changed since.
time_units: generations
demes:
  - name: B
    start_time: .inf
    epochs:
      - start_size: 8201
        end_time: 4304.0
      - start_size: 1526
        end_time: 0