Input TRS:
    1: f(act(),y) -> f(el(nact()),y)
    2: f(x,nact()) -> f(x,act())
    3: act() -> el(nact())
    4: l(el(x)) -> el(l(x))
    5: el(r(x)) -> r(el(x))
   e1: nact() ->= l(nact())	[relative]
   e2: nact() ->= r(nact())	[relative]
Weak rule e1 calls a strict rule