Deme R maintained a population of 8247 until there was a shift 5389.1 generations ago that changed its numbers to 9675, a figure that has remained the same since.
time_units: generations
demes:
  - name: R
    start_time: .inf
    epochs:
      - start_size: 8247
        end_time: 5389.1
      - start_size: 9675
        end_time: 0