mdp
const int N;

const double p = 0.5;

module main
	x : [0..N] init N/2;
	
	[right] x<N -> p : (x'=x+1) + (1-p) : (x'=x);
	[left] x>0 -> p : (x'=x-1) + (1-p) : (x'=x);
	
endmodule

rewards "r"
 [right] true : 1;
 endrewards
 

 rewards "l"
  [left] true : 1;
  endrewards