dtmc

const double p;
formula outcome = (s>0 ? s-1 : -1);

module M1
  s: [0..4] init 0;

  [] s=0 -> 1/2:(s'=0) + 1/8:(s'=1) + 1/8:(s'=2) + 1/8:(s'=3) + 1/8:(s'=4);
endmodule