WORST_CASE(?,O(n^1))
* Step 1: Ara WORST_CASE(?,O(n^1))
    + Considered Problem:
        - Strict TRS:
            activate(X) -> X
            activate(n__add(X1,X2)) -> add(X1,X2)
            activate(n__from(X)) -> from(X)
            activate(n__fst(X1,X2)) -> fst(X1,X2)
            activate(n__len(X)) -> len(X)
            add(X1,X2) -> n__add(X1,X2)
            add(0(),X) -> X
            add(s(X),Y) -> s(n__add(activate(X),Y))
            from(X) -> cons(X,n__from(s(X)))
            from(X) -> n__from(X)
            fst(X1,X2) -> n__fst(X1,X2)
            fst(0(),Z) -> nil()
            fst(s(X),cons(Y,Z)) -> cons(Y,n__fst(activate(X),activate(Z)))
            len(X) -> n__len(X)
            len(cons(X,Z)) -> s(n__len(activate(Z)))
            len(nil()) -> 0()
        - Signature:
            {activate/1,add/2,from/1,fst/2,len/1} / {0/0,cons/2,n__add/2,n__from/1,n__fst/2,n__len/1,nil/0,s/1}
        - Obligation:
            innermost runtime complexity wrt. defined symbols {activate,add,from,fst,len} and constructors {0,cons
            ,n__add,n__from,n__fst,n__len,nil,s}
    + Applied Processor:
        Ara {heuristics_ = NoHeuristics, minDegree = 1, maxDegree = 3, araTimeout = 60, araFindStrictRules = Nothing, araSmtSolver = MiniSMT}
    + Details:
        Signatures used:
        ----------------
          0 :: [] -(0)-> A(2)
          0 :: [] -(0)-> A(5)
          activate :: [A(2)] -(3)-> A(0)
          add :: [A(2) x A(0)] -(2)-> A(0)
          cons :: [A(0) x A(2)] -(2)-> A(2)
          cons :: [A(0) x A(0)] -(0)-> A(0)
          from :: [A(0)] -(1)-> A(0)
          fst :: [A(2) x A(2)] -(3)-> A(0)
          len :: [A(2)] -(4)-> A(0)
          n__add :: [A(2) x A(0)] -(0)-> A(2)
          n__add :: [A(0) x A(0)] -(0)-> A(0)
          n__from :: [A(0)] -(0)-> A(2)
          n__from :: [A(0)] -(0)-> A(0)
          n__fst :: [A(2) x A(2)] -(2)-> A(2)
          n__fst :: [A(1) x A(1)] -(1)-> A(1)
          n__fst :: [A(0) x A(0)] -(0)-> A(0)
          n__len :: [A(2)] -(2)-> A(2)
          n__len :: [A(0)] -(0)-> A(0)
          nil :: [] -(0)-> A(2)
          nil :: [] -(0)-> A(1)
          s :: [A(2)] -(2)-> A(2)
          s :: [A(0)] -(0)-> A(0)
        
        
        Cost-free Signatures used:
        --------------------------
          0 :: [] -(0)-> A_cf(0)
          activate :: [A_cf(0)] -(0)-> A_cf(0)
          add :: [A_cf(0) x A_cf(0)] -(0)-> A_cf(0)
          cons :: [A_cf(0) x A_cf(0)] -(0)-> A_cf(0)
          from :: [A_cf(0)] -(0)-> A_cf(0)
          fst :: [A_cf(0) x A_cf(0)] -(0)-> A_cf(0)
          len :: [A_cf(0)] -(0)-> A_cf(0)
          n__add :: [A_cf(0) x A_cf(0)] -(0)-> A_cf(0)
          n__from :: [A_cf(0)] -(0)-> A_cf(0)
          n__fst :: [A_cf(0) x A_cf(0)] -(0)-> A_cf(0)
          n__len :: [A_cf(0)] -(0)-> A_cf(0)
          nil :: [] -(0)-> A_cf(0)
          s :: [A_cf(0)] -(0)-> A_cf(0)
        
        
        Base Constructor Signatures used:
        ---------------------------------
          0_A :: [] -(0)-> A(1)
          cons_A :: [A(0) x A(1)] -(1)-> A(1)
          n__add_A :: [A(0) x A(0)] -(0)-> A(1)
          n__from_A :: [A(0)] -(0)-> A(1)
          n__fst_A :: [A(0) x A(0)] -(1)-> A(1)
          n__len_A :: [A(0)] -(1)-> A(1)
          nil_A :: [] -(0)-> A(1)
          s_A :: [A(1)] -(1)-> A(1)
        
* Step 2: Open MAYBE
    - Strict TRS:
        activate(X) -> X
        activate(n__add(X1,X2)) -> add(X1,X2)
        activate(n__from(X)) -> from(X)
        activate(n__fst(X1,X2)) -> fst(X1,X2)
        activate(n__len(X)) -> len(X)
        add(X1,X2) -> n__add(X1,X2)
        add(0(),X) -> X
        add(s(X),Y) -> s(n__add(activate(X),Y))
        from(X) -> cons(X,n__from(s(X)))
        from(X) -> n__from(X)
        fst(X1,X2) -> n__fst(X1,X2)
        fst(0(),Z) -> nil()
        fst(s(X),cons(Y,Z)) -> cons(Y,n__fst(activate(X),activate(Z)))
        len(X) -> n__len(X)
        len(cons(X,Z)) -> s(n__len(activate(Z)))
        len(nil()) -> 0()
    - Signature:
        {activate/1,add/2,from/1,fst/2,len/1} / {0/0,cons/2,n__add/2,n__from/1,n__fst/2,n__len/1,nil/0,s/1}
    - Obligation:
        innermost runtime complexity wrt. defined symbols {activate,add,from,fst,len} and constructors {0,cons
        ,n__add,n__from,n__fst,n__len,nil,s}
Following problems could not be solved:
  - Strict TRS:
      activate(X) -> X
      activate(n__add(X1,X2)) -> add(X1,X2)
      activate(n__from(X)) -> from(X)
      activate(n__fst(X1,X2)) -> fst(X1,X2)
      activate(n__len(X)) -> len(X)
      add(X1,X2) -> n__add(X1,X2)
      add(0(),X) -> X
      add(s(X),Y) -> s(n__add(activate(X),Y))
      from(X) -> cons(X,n__from(s(X)))
      from(X) -> n__from(X)
      fst(X1,X2) -> n__fst(X1,X2)
      fst(0(),Z) -> nil()
      fst(s(X),cons(Y,Z)) -> cons(Y,n__fst(activate(X),activate(Z)))
      len(X) -> n__len(X)
      len(cons(X,Z)) -> s(n__len(activate(Z)))
      len(nil()) -> 0()
  - Signature:
      {activate/1,add/2,from/1,fst/2,len/1} / {0/0,cons/2,n__add/2,n__from/1,n__fst/2,n__len/1,nil/0,s/1}
  - Obligation:
      innermost runtime complexity wrt. defined symbols {activate,add,from,fst,len} and constructors {0,cons
      ,n__add,n__from,n__fst,n__len,nil,s}
WORST_CASE(?,O(n^1))