Until 7286.16 generations ago, the population of deme S was 7061. At that point, it changed to 3790, where it has stayed up to now.
time_units: generations
demes:
  - name: S
    start_time: .inf
    epochs:
      - start_size: 7061
        end_time: 7286.16
      - start_size: 3790
        end_time: 0