(RULES
  i 0 -> p s p s 0 p s p s ,
  i s -> p s p s s j p s p s p p p p s s s s ,

  j 0 -> p s p p s s 0 p s p s ,
  j s -> s s s s p p s s i p s p s ,

  p p s -> p ,
  p s -> ,
  p 0 -> 0 s s s s s s s s
)