Input TRS:
    1: s(a(x)) -> s(b(x))
    2: b(b(x)) -> a(x)
   e1: f(s(x),y) ->= f(x,s(y))	[relative]
   e2: s(a(x)) ->= a(s(x))	[relative]
   e3: s(b(x)) ->= b(s(x))	[relative]
   e4: a(s(x)) ->= s(a(x))	[relative]
   e5: b(s(x)) ->= s(b(x))	[relative]
Weak rule e2 calls a strict rule