Deme J had an initial size of 2324 until 2023.0 generations ago. At that time, its population size changed to 3191, and has remained there till current time.
time_units: generations
demes:
  - name: J
    start_time: .inf
    epochs:
      - start_size: 2324
        end_time: 2023.0
      - start_size: 3191
        end_time: 0