MAYBE
* Step 1: DependencyPairs MAYBE
    + Considered Problem:
        - Strict TRS:
            a__2nd(X) -> 2nd(X)
            a__2nd(cons(X,X1)) -> a__2nd(cons1(mark(X),mark(X1)))
            a__2nd(cons1(X,cons(Y,Z))) -> mark(Y)
            a__from(X) -> cons(mark(X),from(s(X)))
            a__from(X) -> from(X)
            mark(2nd(X)) -> a__2nd(mark(X))
            mark(cons(X1,X2)) -> cons(mark(X1),X2)
            mark(cons1(X1,X2)) -> cons1(mark(X1),mark(X2))
            mark(from(X)) -> a__from(mark(X))
            mark(s(X)) -> s(mark(X))
        - Signature:
            {a__2nd/1,a__from/1,mark/1} / {2nd/1,cons/2,cons1/2,from/1,s/1}
        - Obligation:
            innermost runtime complexity wrt. defined symbols {a__2nd,a__from,mark} and constructors {2nd,cons,cons1
            ,from,s}
    + Applied Processor:
        DependencyPairs {dpKind_ = DT}
    + Details:
        We add the following dependency tuples:
        
        Strict DPs
          a__2nd#(X) -> c_1()
          a__2nd#(cons(X,X1)) -> c_2(a__2nd#(cons1(mark(X),mark(X1))),mark#(X),mark#(X1))
          a__2nd#(cons1(X,cons(Y,Z))) -> c_3(mark#(Y))
          a__from#(X) -> c_4(mark#(X))
          a__from#(X) -> c_5()
          mark#(2nd(X)) -> c_6(a__2nd#(mark(X)),mark#(X))
          mark#(cons(X1,X2)) -> c_7(mark#(X1))
          mark#(cons1(X1,X2)) -> c_8(mark#(X1),mark#(X2))
          mark#(from(X)) -> c_9(a__from#(mark(X)),mark#(X))
          mark#(s(X)) -> c_10(mark#(X))
        Weak DPs
          
        
        and mark the set of starting terms.
* Step 2: PredecessorEstimation MAYBE
    + Considered Problem:
        - Strict DPs:
            a__2nd#(X) -> c_1()
            a__2nd#(cons(X,X1)) -> c_2(a__2nd#(cons1(mark(X),mark(X1))),mark#(X),mark#(X1))
            a__2nd#(cons1(X,cons(Y,Z))) -> c_3(mark#(Y))
            a__from#(X) -> c_4(mark#(X))
            a__from#(X) -> c_5()
            mark#(2nd(X)) -> c_6(a__2nd#(mark(X)),mark#(X))
            mark#(cons(X1,X2)) -> c_7(mark#(X1))
            mark#(cons1(X1,X2)) -> c_8(mark#(X1),mark#(X2))
            mark#(from(X)) -> c_9(a__from#(mark(X)),mark#(X))
            mark#(s(X)) -> c_10(mark#(X))
        - Weak TRS:
            a__2nd(X) -> 2nd(X)
            a__2nd(cons(X,X1)) -> a__2nd(cons1(mark(X),mark(X1)))
            a__2nd(cons1(X,cons(Y,Z))) -> mark(Y)
            a__from(X) -> cons(mark(X),from(s(X)))
            a__from(X) -> from(X)
            mark(2nd(X)) -> a__2nd(mark(X))
            mark(cons(X1,X2)) -> cons(mark(X1),X2)
            mark(cons1(X1,X2)) -> cons1(mark(X1),mark(X2))
            mark(from(X)) -> a__from(mark(X))
            mark(s(X)) -> s(mark(X))
        - Signature:
            {a__2nd/1,a__from/1,mark/1,a__2nd#/1,a__from#/1,mark#/1} / {2nd/1,cons/2,cons1/2,from/1,s/1,c_1/0,c_2/3
            ,c_3/1,c_4/1,c_5/0,c_6/2,c_7/1,c_8/2,c_9/2,c_10/1}
        - Obligation:
            innermost runtime complexity wrt. defined symbols {a__2nd#,a__from#,mark#} and constructors {2nd,cons,cons1
            ,from,s}
    + Applied Processor:
        PredecessorEstimation {onSelection = all simple predecessor estimation selector}
    + Details:
        We estimate the number of application of
          {1,5}
        by application of
          Pre({1,5}) = {2,6,9}.
        Here rules are labelled as follows:
          1: a__2nd#(X) -> c_1()
          2: a__2nd#(cons(X,X1)) -> c_2(a__2nd#(cons1(mark(X),mark(X1))),mark#(X),mark#(X1))
          3: a__2nd#(cons1(X,cons(Y,Z))) -> c_3(mark#(Y))
          4: a__from#(X) -> c_4(mark#(X))
          5: a__from#(X) -> c_5()
          6: mark#(2nd(X)) -> c_6(a__2nd#(mark(X)),mark#(X))
          7: mark#(cons(X1,X2)) -> c_7(mark#(X1))
          8: mark#(cons1(X1,X2)) -> c_8(mark#(X1),mark#(X2))
          9: mark#(from(X)) -> c_9(a__from#(mark(X)),mark#(X))
          10: mark#(s(X)) -> c_10(mark#(X))
* Step 3: RemoveWeakSuffixes MAYBE
    + Considered Problem:
        - Strict DPs:
            a__2nd#(cons(X,X1)) -> c_2(a__2nd#(cons1(mark(X),mark(X1))),mark#(X),mark#(X1))
            a__2nd#(cons1(X,cons(Y,Z))) -> c_3(mark#(Y))
            a__from#(X) -> c_4(mark#(X))
            mark#(2nd(X)) -> c_6(a__2nd#(mark(X)),mark#(X))
            mark#(cons(X1,X2)) -> c_7(mark#(X1))
            mark#(cons1(X1,X2)) -> c_8(mark#(X1),mark#(X2))
            mark#(from(X)) -> c_9(a__from#(mark(X)),mark#(X))
            mark#(s(X)) -> c_10(mark#(X))
        - Weak DPs:
            a__2nd#(X) -> c_1()
            a__from#(X) -> c_5()
        - Weak TRS:
            a__2nd(X) -> 2nd(X)
            a__2nd(cons(X,X1)) -> a__2nd(cons1(mark(X),mark(X1)))
            a__2nd(cons1(X,cons(Y,Z))) -> mark(Y)
            a__from(X) -> cons(mark(X),from(s(X)))
            a__from(X) -> from(X)
            mark(2nd(X)) -> a__2nd(mark(X))
            mark(cons(X1,X2)) -> cons(mark(X1),X2)
            mark(cons1(X1,X2)) -> cons1(mark(X1),mark(X2))
            mark(from(X)) -> a__from(mark(X))
            mark(s(X)) -> s(mark(X))
        - Signature:
            {a__2nd/1,a__from/1,mark/1,a__2nd#/1,a__from#/1,mark#/1} / {2nd/1,cons/2,cons1/2,from/1,s/1,c_1/0,c_2/3
            ,c_3/1,c_4/1,c_5/0,c_6/2,c_7/1,c_8/2,c_9/2,c_10/1}
        - Obligation:
            innermost runtime complexity wrt. defined symbols {a__2nd#,a__from#,mark#} and constructors {2nd,cons,cons1
            ,from,s}
    + Applied Processor:
        RemoveWeakSuffixes
    + Details:
        Consider the dependency graph
          1:S:a__2nd#(cons(X,X1)) -> c_2(a__2nd#(cons1(mark(X),mark(X1))),mark#(X),mark#(X1))
             -->_3 mark#(s(X)) -> c_10(mark#(X)):8
             -->_2 mark#(s(X)) -> c_10(mark#(X)):8
             -->_3 mark#(from(X)) -> c_9(a__from#(mark(X)),mark#(X)):7
             -->_2 mark#(from(X)) -> c_9(a__from#(mark(X)),mark#(X)):7
             -->_3 mark#(cons1(X1,X2)) -> c_8(mark#(X1),mark#(X2)):6
             -->_2 mark#(cons1(X1,X2)) -> c_8(mark#(X1),mark#(X2)):6
             -->_3 mark#(cons(X1,X2)) -> c_7(mark#(X1)):5
             -->_2 mark#(cons(X1,X2)) -> c_7(mark#(X1)):5
             -->_3 mark#(2nd(X)) -> c_6(a__2nd#(mark(X)),mark#(X)):4
             -->_2 mark#(2nd(X)) -> c_6(a__2nd#(mark(X)),mark#(X)):4
             -->_1 a__2nd#(cons1(X,cons(Y,Z))) -> c_3(mark#(Y)):2
             -->_1 a__2nd#(X) -> c_1():9
          
          2:S:a__2nd#(cons1(X,cons(Y,Z))) -> c_3(mark#(Y))
             -->_1 mark#(s(X)) -> c_10(mark#(X)):8
             -->_1 mark#(from(X)) -> c_9(a__from#(mark(X)),mark#(X)):7
             -->_1 mark#(cons1(X1,X2)) -> c_8(mark#(X1),mark#(X2)):6
             -->_1 mark#(cons(X1,X2)) -> c_7(mark#(X1)):5
             -->_1 mark#(2nd(X)) -> c_6(a__2nd#(mark(X)),mark#(X)):4
          
          3:S:a__from#(X) -> c_4(mark#(X))
             -->_1 mark#(s(X)) -> c_10(mark#(X)):8
             -->_1 mark#(from(X)) -> c_9(a__from#(mark(X)),mark#(X)):7
             -->_1 mark#(cons1(X1,X2)) -> c_8(mark#(X1),mark#(X2)):6
             -->_1 mark#(cons(X1,X2)) -> c_7(mark#(X1)):5
             -->_1 mark#(2nd(X)) -> c_6(a__2nd#(mark(X)),mark#(X)):4
          
          4:S:mark#(2nd(X)) -> c_6(a__2nd#(mark(X)),mark#(X))
             -->_2 mark#(s(X)) -> c_10(mark#(X)):8
             -->_2 mark#(from(X)) -> c_9(a__from#(mark(X)),mark#(X)):7
             -->_2 mark#(cons1(X1,X2)) -> c_8(mark#(X1),mark#(X2)):6
             -->_2 mark#(cons(X1,X2)) -> c_7(mark#(X1)):5
             -->_1 a__2nd#(X) -> c_1():9
             -->_2 mark#(2nd(X)) -> c_6(a__2nd#(mark(X)),mark#(X)):4
             -->_1 a__2nd#(cons1(X,cons(Y,Z))) -> c_3(mark#(Y)):2
             -->_1 a__2nd#(cons(X,X1)) -> c_2(a__2nd#(cons1(mark(X),mark(X1))),mark#(X),mark#(X1)):1
          
          5:S:mark#(cons(X1,X2)) -> c_7(mark#(X1))
             -->_1 mark#(s(X)) -> c_10(mark#(X)):8
             -->_1 mark#(from(X)) -> c_9(a__from#(mark(X)),mark#(X)):7
             -->_1 mark#(cons1(X1,X2)) -> c_8(mark#(X1),mark#(X2)):6
             -->_1 mark#(cons(X1,X2)) -> c_7(mark#(X1)):5
             -->_1 mark#(2nd(X)) -> c_6(a__2nd#(mark(X)),mark#(X)):4
          
          6:S:mark#(cons1(X1,X2)) -> c_8(mark#(X1),mark#(X2))
             -->_2 mark#(s(X)) -> c_10(mark#(X)):8
             -->_1 mark#(s(X)) -> c_10(mark#(X)):8
             -->_2 mark#(from(X)) -> c_9(a__from#(mark(X)),mark#(X)):7
             -->_1 mark#(from(X)) -> c_9(a__from#(mark(X)),mark#(X)):7
             -->_2 mark#(cons1(X1,X2)) -> c_8(mark#(X1),mark#(X2)):6
             -->_1 mark#(cons1(X1,X2)) -> c_8(mark#(X1),mark#(X2)):6
             -->_2 mark#(cons(X1,X2)) -> c_7(mark#(X1)):5
             -->_1 mark#(cons(X1,X2)) -> c_7(mark#(X1)):5
             -->_2 mark#(2nd(X)) -> c_6(a__2nd#(mark(X)),mark#(X)):4
             -->_1 mark#(2nd(X)) -> c_6(a__2nd#(mark(X)),mark#(X)):4
          
          7:S:mark#(from(X)) -> c_9(a__from#(mark(X)),mark#(X))
             -->_2 mark#(s(X)) -> c_10(mark#(X)):8
             -->_1 a__from#(X) -> c_5():10
             -->_2 mark#(from(X)) -> c_9(a__from#(mark(X)),mark#(X)):7
             -->_2 mark#(cons1(X1,X2)) -> c_8(mark#(X1),mark#(X2)):6
             -->_2 mark#(cons(X1,X2)) -> c_7(mark#(X1)):5
             -->_2 mark#(2nd(X)) -> c_6(a__2nd#(mark(X)),mark#(X)):4
             -->_1 a__from#(X) -> c_4(mark#(X)):3
          
          8:S:mark#(s(X)) -> c_10(mark#(X))
             -->_1 mark#(s(X)) -> c_10(mark#(X)):8
             -->_1 mark#(from(X)) -> c_9(a__from#(mark(X)),mark#(X)):7
             -->_1 mark#(cons1(X1,X2)) -> c_8(mark#(X1),mark#(X2)):6
             -->_1 mark#(cons(X1,X2)) -> c_7(mark#(X1)):5
             -->_1 mark#(2nd(X)) -> c_6(a__2nd#(mark(X)),mark#(X)):4
          
          9:W:a__2nd#(X) -> c_1()
             
          
          10:W:a__from#(X) -> c_5()
             
          
        The following weak DPs constitute a sub-graph of the DG that is closed under successors. The DPs are removed.
          9: a__2nd#(X) -> c_1()
          10: a__from#(X) -> c_5()
* Step 4: Failure MAYBE
  + Considered Problem:
      - Strict DPs:
          a__2nd#(cons(X,X1)) -> c_2(a__2nd#(cons1(mark(X),mark(X1))),mark#(X),mark#(X1))
          a__2nd#(cons1(X,cons(Y,Z))) -> c_3(mark#(Y))
          a__from#(X) -> c_4(mark#(X))
          mark#(2nd(X)) -> c_6(a__2nd#(mark(X)),mark#(X))
          mark#(cons(X1,X2)) -> c_7(mark#(X1))
          mark#(cons1(X1,X2)) -> c_8(mark#(X1),mark#(X2))
          mark#(from(X)) -> c_9(a__from#(mark(X)),mark#(X))
          mark#(s(X)) -> c_10(mark#(X))
      - Weak TRS:
          a__2nd(X) -> 2nd(X)
          a__2nd(cons(X,X1)) -> a__2nd(cons1(mark(X),mark(X1)))
          a__2nd(cons1(X,cons(Y,Z))) -> mark(Y)
          a__from(X) -> cons(mark(X),from(s(X)))
          a__from(X) -> from(X)
          mark(2nd(X)) -> a__2nd(mark(X))
          mark(cons(X1,X2)) -> cons(mark(X1),X2)
          mark(cons1(X1,X2)) -> cons1(mark(X1),mark(X2))
          mark(from(X)) -> a__from(mark(X))
          mark(s(X)) -> s(mark(X))
      - Signature:
          {a__2nd/1,a__from/1,mark/1,a__2nd#/1,a__from#/1,mark#/1} / {2nd/1,cons/2,cons1/2,from/1,s/1,c_1/0,c_2/3
          ,c_3/1,c_4/1,c_5/0,c_6/2,c_7/1,c_8/2,c_9/2,c_10/1}
      - Obligation:
          innermost runtime complexity wrt. defined symbols {a__2nd#,a__from#,mark#} and constructors {2nd,cons,cons1
          ,from,s}
  + Applied Processor:
      EmptyProcessor
  + Details:
      The problem is still open.
MAYBE