The population of deme M held at 3287 until 170.859 generations back, when it changed reaching 3383, which has been constant since then.
time_units: generations
demes:
  - name: M
    start_time: .inf
    epochs:
      - start_size: 3287
        end_time: 170.859
      - start_size: 3383
        end_time: 0