(VAR x )
(RULES 
cond(true,x) -> cond(odd(x),p(p(p(x))))
odd(0) -> false
odd(s(0)) -> true
odd(s(s(x))) -> odd(x)
p(0) -> 0
p(s(x)) -> x
)

(COMMENT
while odd(x)
do
  x:=p(p(p(x)))
od
)