Until 1141.3 generations ago, the population of deme Q was 3431. At that point, it changed to 212, where it has stayed up to now.
time_units: generations
demes:
  - name: Q
    start_time: .inf
    epochs:
      - start_size: 3431
        end_time: 1141.3
      - start_size: 212
        end_time: 0