MAYBE
* Step 1: Failure MAYBE
  + Considered Problem:
      - Strict TRS:
          a__U11(X1,X2) -> U11(X1,X2)
          a__U11(tt(),V1) -> a__U12(a__isNatList(V1))
          a__U12(X) -> U12(X)
          a__U12(tt()) -> tt()
          a__U21(X1,X2) -> U21(X1,X2)
          a__U21(tt(),V1) -> a__U22(a__isNat(V1))
          a__U22(X) -> U22(X)
          a__U22(tt()) -> tt()
          a__U31(X1,X2) -> U31(X1,X2)
          a__U31(tt(),V) -> a__U32(a__isNatList(V))
          a__U32(X) -> U32(X)
          a__U32(tt()) -> tt()
          a__U41(X1,X2,X3) -> U41(X1,X2,X3)
          a__U41(tt(),V1,V2) -> a__U42(a__isNat(V1),V2)
          a__U42(X1,X2) -> U42(X1,X2)
          a__U42(tt(),V2) -> a__U43(a__isNatIList(V2))
          a__U43(X) -> U43(X)
          a__U43(tt()) -> tt()
          a__U51(X1,X2,X3) -> U51(X1,X2,X3)
          a__U51(tt(),V1,V2) -> a__U52(a__isNat(V1),V2)
          a__U52(X1,X2) -> U52(X1,X2)
          a__U52(tt(),V2) -> a__U53(a__isNatList(V2))
          a__U53(X) -> U53(X)
          a__U53(tt()) -> tt()
          a__U61(X1,X2) -> U61(X1,X2)
          a__U61(tt(),L) -> s(a__length(mark(L)))
          a__and(X1,X2) -> and(X1,X2)
          a__and(tt(),X) -> mark(X)
          a__isNat(X) -> isNat(X)
          a__isNat(0()) -> tt()
          a__isNat(length(V1)) -> a__U11(a__isNatIListKind(V1),V1)
          a__isNat(s(V1)) -> a__U21(a__isNatKind(V1),V1)
          a__isNatIList(V) -> a__U31(a__isNatIListKind(V),V)
          a__isNatIList(X) -> isNatIList(X)
          a__isNatIList(cons(V1,V2)) -> a__U41(a__and(a__isNatKind(V1),isNatIListKind(V2)),V1,V2)
          a__isNatIList(zeros()) -> tt()
          a__isNatIListKind(X) -> isNatIListKind(X)
          a__isNatIListKind(cons(V1,V2)) -> a__and(a__isNatKind(V1),isNatIListKind(V2))
          a__isNatIListKind(nil()) -> tt()
          a__isNatIListKind(zeros()) -> tt()
          a__isNatKind(X) -> isNatKind(X)
          a__isNatKind(0()) -> tt()
          a__isNatKind(length(V1)) -> a__isNatIListKind(V1)
          a__isNatKind(s(V1)) -> a__isNatKind(V1)
          a__isNatList(X) -> isNatList(X)
          a__isNatList(cons(V1,V2)) -> a__U51(a__and(a__isNatKind(V1),isNatIListKind(V2)),V1,V2)
          a__isNatList(nil()) -> tt()
          a__length(X) -> length(X)
          a__length(cons(N,L)) -> a__U61(a__and(a__and(a__isNatList(L),isNatIListKind(L)),and(isNat(N),isNatKind(N)))
                                        ,L)
          a__length(nil()) -> 0()
          a__zeros() -> cons(0(),zeros())
          a__zeros() -> zeros()
          mark(0()) -> 0()
          mark(U11(X1,X2)) -> a__U11(mark(X1),X2)
          mark(U12(X)) -> a__U12(mark(X))
          mark(U21(X1,X2)) -> a__U21(mark(X1),X2)
          mark(U22(X)) -> a__U22(mark(X))
          mark(U31(X1,X2)) -> a__U31(mark(X1),X2)
          mark(U32(X)) -> a__U32(mark(X))
          mark(U41(X1,X2,X3)) -> a__U41(mark(X1),X2,X3)
          mark(U42(X1,X2)) -> a__U42(mark(X1),X2)
          mark(U43(X)) -> a__U43(mark(X))
          mark(U51(X1,X2,X3)) -> a__U51(mark(X1),X2,X3)
          mark(U52(X1,X2)) -> a__U52(mark(X1),X2)
          mark(U53(X)) -> a__U53(mark(X))
          mark(U61(X1,X2)) -> a__U61(mark(X1),X2)
          mark(and(X1,X2)) -> a__and(mark(X1),X2)
          mark(cons(X1,X2)) -> cons(mark(X1),X2)
          mark(isNat(X)) -> a__isNat(X)
          mark(isNatIList(X)) -> a__isNatIList(X)
          mark(isNatIListKind(X)) -> a__isNatIListKind(X)
          mark(isNatKind(X)) -> a__isNatKind(X)
          mark(isNatList(X)) -> a__isNatList(X)
          mark(length(X)) -> a__length(mark(X))
          mark(nil()) -> nil()
          mark(s(X)) -> s(mark(X))
          mark(tt()) -> tt()
          mark(zeros()) -> a__zeros()
      - Signature:
          {a__U11/2,a__U12/1,a__U21/2,a__U22/1,a__U31/2,a__U32/1,a__U41/3,a__U42/2,a__U43/1,a__U51/3,a__U52/2,a__U53/1
          ,a__U61/2,a__and/2,a__isNat/1,a__isNatIList/1,a__isNatIListKind/1,a__isNatKind/1,a__isNatList/1,a__length/1
          ,a__zeros/0,mark/1} / {0/0,U11/2,U12/1,U21/2,U22/1,U31/2,U32/1,U41/3,U42/2,U43/1,U51/3,U52/2,U53/1,U61/2
          ,and/2,cons/2,isNat/1,isNatIList/1,isNatIListKind/1,isNatKind/1,isNatList/1,length/1,nil/0,s/1,tt/0,zeros/0}
      - Obligation:
          innermost runtime complexity wrt. defined symbols {a__U11,a__U12,a__U21,a__U22,a__U31,a__U32,a__U41,a__U42
          ,a__U43,a__U51,a__U52,a__U53,a__U61,a__and,a__isNat,a__isNatIList,a__isNatIListKind,a__isNatKind
          ,a__isNatList,a__length,a__zeros,mark} and constructors {0,U11,U12,U21,U22,U31,U32,U41,U42,U43,U51,U52,U53
          ,U61,and,cons,isNat,isNatIList,isNatIListKind,isNatKind,isNatList,length,nil,s,tt,zeros}
  + Applied Processor:
      MI {miKind = Automaton Nothing, miDimension = 3, miUArgs = NoUArgs, miURules = NoURules, miSelector = Nothing}
  + Details:
      Incompatible
MAYBE