Until a shift occurred 613.766 generations ago, deme R's population was consistently 9801. Since then, it decreased to 2193, a number that has remained unchanged to the current time.
time_units: generations
demes:
  - name: R
    start_time: .inf
    epochs:
      - start_size: 9801
        end_time: 613.766
      - start_size: 2193
        end_time: 0