For deme F, the population count was 7646 until a change 3884.84 generations ago, where it decreased to 1450, remaining steady thereafter.
time_units: generations
demes:
  - name: F
    start_time: .inf
    epochs:
      - start_size: 7646
        end_time: 3884.84
      - start_size: 1450
        end_time: 0