The number of individuals in deme N remained at 9691 until 581.6777 generations ago, at which time it changed to a new stable size of 120.
time_units: generations
demes:
  - name: N
    start_time: .inf
    epochs:
      - start_size: 9691
        end_time: 581.6777
      - start_size: 120
        end_time: 0