For deme R, the population count was 4852 until a change 5761.0 generations ago, where it reduced to 4252, remaining steady thereafter.
time_units: generations
demes:
  - name: R
    start_time: .inf
    epochs:
      - start_size: 4852
        end_time: 5761.0
      - start_size: 4252
        end_time: 0