type mode = H | M | L

node server(max:int) = (load:int)
  contract
  assume (max >= 5)
  enforce (load <= max)
  with (c:mode)
let
  switch c
  | H do load = 20
  | M do load = 10
  | L do load = 0
  end
tel

type degmode = Normal | Degraded
  
node degraded_server(max:int) = (load:int)
  contract
  assume (max >= 10)
  enforce (load <= max)
with (cm:mode;cd:degmode)
let
    switch cd
    | Normal do
        switch cm
        | H do load = 20
        | M do load = 10
        | L do load = 0
        end
    | Degraded do load = 2
    end
tel

(* CHECK main *)
node main() = (ok:bool)
  var max, load1, load2 : int;
let
    load1 = 0;
  load2 = degraded_server(max);
  max = 10;
  ok = (load1 <= max) & (load2 <= max);
tel