WORST_CASE(?,O(n^2))
* Step 1: Ara WORST_CASE(?,O(n^2))
    + Considered Problem:
        - Strict TRS:
            a__add(X1,X2) -> add(X1,X2)
            a__add(0(),X) -> mark(X)
            a__add(s(X),Y) -> s(add(X,Y))
            a__from(X) -> cons(mark(X),from(s(X)))
            a__from(X) -> from(X)
            a__fst(X1,X2) -> fst(X1,X2)
            a__fst(0(),Z) -> nil()
            a__fst(s(X),cons(Y,Z)) -> cons(mark(Y),fst(X,Z))
            a__len(X) -> len(X)
            a__len(cons(X,Z)) -> s(len(Z))
            a__len(nil()) -> 0()
            mark(0()) -> 0()
            mark(add(X1,X2)) -> a__add(mark(X1),mark(X2))
            mark(cons(X1,X2)) -> cons(mark(X1),X2)
            mark(from(X)) -> a__from(mark(X))
            mark(fst(X1,X2)) -> a__fst(mark(X1),mark(X2))
            mark(len(X)) -> a__len(mark(X))
            mark(nil()) -> nil()
            mark(s(X)) -> s(X)
        - Signature:
            {a__add/2,a__from/1,a__fst/2,a__len/1,mark/1} / {0/0,add/2,cons/2,from/1,fst/2,len/1,nil/0,s/1}
        - Obligation:
            innermost runtime complexity wrt. defined symbols {a__add,a__from,a__fst,a__len,mark} and constructors {0
            ,add,cons,from,fst,len,nil,s}
    + Applied Processor:
        Ara {heuristics_ = NoHeuristics, minDegree = 1, maxDegree = 3, araTimeout = 60, araFindStrictRules = Nothing, araSmtSolver = Z3}
    + Details:
        Signatures used:
        ----------------
          0 :: [] -(0)-> A(6, 3)
          0 :: [] -(0)-> A(9, 3)
          0 :: [] -(0)-> A(13, 5)
          a__add :: [A(6, 3) x A(9, 3)] -(7)-> A(6, 3)
          a__from :: [A(9, 3)] -(8)-> A(6, 3)
          a__fst :: [A(6, 3) x A(9, 3)] -(7)-> A(6, 3)
          a__len :: [A(6, 3)] -(7)-> A(6, 3)
          add :: [A(9, 3) x A(12, 3)] -(9)-> A(9, 3)
          add :: [A(6, 3) x A(9, 3)] -(6)-> A(6, 3)
          add :: [A(0, 0) x A(0, 0)] -(0)-> A(0, 0)
          cons :: [A(9, 3) x A(0, 0)] -(9)-> A(9, 3)
          cons :: [A(6, 3) x A(0, 0)] -(6)-> A(6, 3)
          from :: [A(12, 3)] -(9)-> A(9, 3)
          from :: [A(0, 0)] -(0)-> A(0, 0)
          from :: [A(9, 3)] -(6)-> A(6, 3)
          fst :: [A(9, 3) x A(12, 3)] -(9)-> A(9, 3)
          fst :: [A(6, 3) x A(9, 3)] -(6)-> A(6, 3)
          fst :: [A(0, 0) x A(0, 0)] -(0)-> A(0, 0)
          len :: [A(9, 3)] -(9)-> A(9, 3)
          len :: [A(6, 3)] -(6)-> A(6, 3)
          len :: [A(0, 0)] -(0)-> A(0, 0)
          mark :: [A(9, 3)] -(1)-> A(6, 3)
          nil :: [] -(0)-> A(6, 3)
          nil :: [] -(0)-> A(9, 3)
          nil :: [] -(0)-> A(13, 5)
          s :: [A(0, 0)] -(3)-> A(6, 3)
          s :: [A(0, 0)] -(3)-> A(9, 3)
          s :: [A(0, 0)] -(4)-> A(12, 4)
          s :: [A(0, 0)] -(0)-> A(0, 0)
          s :: [A(0, 0)] -(9)-> A(10, 9)
          s :: [A(0, 0)] -(3)-> A(10, 3)
        
        
        Cost-free Signatures used:
        --------------------------
          0 :: [] -(0)-> A_cf(0, 0)
          0 :: [] -(0)-> A_cf(3, 0)
          0 :: [] -(0)-> A_cf(3, 2)
          a__add :: [A_cf(0, 0) x A_cf(0, 0)] -(0)-> A_cf(0, 0)
          a__add :: [A_cf(3, 0) x A_cf(3, 0)] -(3)-> A_cf(3, 0)
          a__from :: [A_cf(0, 0)] -(0)-> A_cf(0, 0)
          a__from :: [A_cf(3, 0)] -(3)-> A_cf(3, 0)
          a__fst :: [A_cf(0, 0) x A_cf(0, 0)] -(0)-> A_cf(0, 0)
          a__fst :: [A_cf(3, 0) x A_cf(3, 0)] -(3)-> A_cf(3, 0)
          a__len :: [A_cf(0, 0)] -(0)-> A_cf(0, 0)
          a__len :: [A_cf(3, 0)] -(3)-> A_cf(3, 0)
          add :: [A_cf(0, 0) x A_cf(0, 0)] -(0)-> A_cf(0, 0)
          add :: [A_cf(3, 0) x A_cf(3, 0)] -(3)-> A_cf(3, 0)
          cons :: [A_cf(0, 0) x A_cf(0, 0)] -(0)-> A_cf(0, 0)
          cons :: [A_cf(3, 0) x A_cf(0, 0)] -(3)-> A_cf(3, 0)
          from :: [A_cf(0, 0)] -(0)-> A_cf(0, 0)
          from :: [A_cf(3, 0)] -(3)-> A_cf(3, 0)
          fst :: [A_cf(0, 0) x A_cf(0, 0)] -(0)-> A_cf(0, 0)
          fst :: [A_cf(3, 0) x A_cf(3, 0)] -(3)-> A_cf(3, 0)
          len :: [A_cf(0, 0)] -(0)-> A_cf(0, 0)
          len :: [A_cf(3, 0)] -(3)-> A_cf(3, 0)
          mark :: [A_cf(0, 0)] -(0)-> A_cf(0, 0)
          mark :: [A_cf(3, 0)] -(0)-> A_cf(3, 0)
          nil :: [] -(0)-> A_cf(0, 0)
          nil :: [] -(0)-> A_cf(3, 0)
          nil :: [] -(0)-> A_cf(3, 2)
          s :: [A_cf(0, 0)] -(0)-> A_cf(0, 0)
          s :: [A_cf(0, 0)] -(0)-> A_cf(3, 0)
          s :: [A_cf(0, 0)] -(2)-> A_cf(11, 2)
          s :: [A_cf(0, 0)] -(6)-> A_cf(4, 6)
          s :: [A_cf(0, 0)] -(0)-> A_cf(14, 0)
          s :: [A_cf(0, 0)] -(2)-> A_cf(10, 2)
          s :: [A_cf(0, 0)] -(1)-> A_cf(8, 1)
          s :: [A_cf(0, 0)] -(3)-> A_cf(12, 3)
          s :: [A_cf(0, 0)] -(0)-> A_cf(8, 0)
          s :: [A_cf(0, 0)] -(5)-> A_cf(4, 5)
          s :: [A_cf(0, 0)] -(0)-> A_cf(5, 0)
        
        
        Base Constructor Signatures used:
        ---------------------------------
          0_A :: [] -(0)-> A(1, 0)
          0_A :: [] -(0)-> A(0, 1)
          add_A :: [A(1, 0) x A(1, 0)] -(1)-> A(1, 0)
          add_A :: [A(0, 1) x A(1, 1)] -(0)-> A(0, 1)
          cons_A :: [A(1, 0) x A(0, 0)] -(1)-> A(1, 0)
          cons_A :: [A(0, 1) x A(0, 0)] -(0)-> A(0, 1)
          from_A :: [A(1, 0)] -(1)-> A(1, 0)
          from_A :: [A(1, 1)] -(0)-> A(0, 1)
          fst_A :: [A(1, 0) x A(1, 0)] -(1)-> A(1, 0)
          fst_A :: [A(0, 1) x A(1, 1)] -(0)-> A(0, 1)
          len_A :: [A(1, 0)] -(1)-> A(1, 0)
          len_A :: [A(0, 1)] -(0)-> A(0, 1)
          nil_A :: [] -(0)-> A(1, 0)
          nil_A :: [] -(0)-> A(0, 1)
          s_A :: [A(0, 0)] -(0)-> A(1, 0)
          s_A :: [A(0, 0)] -(1)-> A(0, 1)
        
* Step 2: Open MAYBE
    - Strict TRS:
        a__add(X1,X2) -> add(X1,X2)
        a__add(0(),X) -> mark(X)
        a__add(s(X),Y) -> s(add(X,Y))
        a__from(X) -> cons(mark(X),from(s(X)))
        a__from(X) -> from(X)
        a__fst(X1,X2) -> fst(X1,X2)
        a__fst(0(),Z) -> nil()
        a__fst(s(X),cons(Y,Z)) -> cons(mark(Y),fst(X,Z))
        a__len(X) -> len(X)
        a__len(cons(X,Z)) -> s(len(Z))
        a__len(nil()) -> 0()
        mark(0()) -> 0()
        mark(add(X1,X2)) -> a__add(mark(X1),mark(X2))
        mark(cons(X1,X2)) -> cons(mark(X1),X2)
        mark(from(X)) -> a__from(mark(X))
        mark(fst(X1,X2)) -> a__fst(mark(X1),mark(X2))
        mark(len(X)) -> a__len(mark(X))
        mark(nil()) -> nil()
        mark(s(X)) -> s(X)
    - Signature:
        {a__add/2,a__from/1,a__fst/2,a__len/1,mark/1} / {0/0,add/2,cons/2,from/1,fst/2,len/1,nil/0,s/1}
    - Obligation:
        innermost runtime complexity wrt. defined symbols {a__add,a__from,a__fst,a__len,mark} and constructors {0
        ,add,cons,from,fst,len,nil,s}
Following problems could not be solved:
  - Strict TRS:
      a__add(X1,X2) -> add(X1,X2)
      a__add(0(),X) -> mark(X)
      a__add(s(X),Y) -> s(add(X,Y))
      a__from(X) -> cons(mark(X),from(s(X)))
      a__from(X) -> from(X)
      a__fst(X1,X2) -> fst(X1,X2)
      a__fst(0(),Z) -> nil()
      a__fst(s(X),cons(Y,Z)) -> cons(mark(Y),fst(X,Z))
      a__len(X) -> len(X)
      a__len(cons(X,Z)) -> s(len(Z))
      a__len(nil()) -> 0()
      mark(0()) -> 0()
      mark(add(X1,X2)) -> a__add(mark(X1),mark(X2))
      mark(cons(X1,X2)) -> cons(mark(X1),X2)
      mark(from(X)) -> a__from(mark(X))
      mark(fst(X1,X2)) -> a__fst(mark(X1),mark(X2))
      mark(len(X)) -> a__len(mark(X))
      mark(nil()) -> nil()
      mark(s(X)) -> s(X)
  - Signature:
      {a__add/2,a__from/1,a__fst/2,a__len/1,mark/1} / {0/0,add/2,cons/2,from/1,fst/2,len/1,nil/0,s/1}
  - Obligation:
      innermost runtime complexity wrt. defined symbols {a__add,a__from,a__fst,a__len,mark} and constructors {0
      ,add,cons,from,fst,len,nil,s}
WORST_CASE(?,O(n^2))