MAYBE
* Step 1: Failure MAYBE
  + Considered Problem:
      - Strict TRS:
          a__U11(X) -> U11(X)
          a__U11(tt()) -> tt()
          a__U21(X) -> U21(X)
          a__U21(tt()) -> tt()
          a__U31(X) -> U31(X)
          a__U31(tt()) -> tt()
          a__U41(X1,X2) -> U41(X1,X2)
          a__U41(tt(),V2) -> a__U42(a__isNatIList(V2))
          a__U42(X) -> U42(X)
          a__U42(tt()) -> tt()
          a__U51(X1,X2) -> U51(X1,X2)
          a__U51(tt(),V2) -> a__U52(a__isNatList(V2))
          a__U52(X) -> U52(X)
          a__U52(tt()) -> tt()
          a__U61(X1,X2) -> U61(X1,X2)
          a__U61(tt(),V2) -> a__U62(a__isNatIList(V2))
          a__U62(X) -> U62(X)
          a__U62(tt()) -> tt()
          a__U71(X1,X2,X3) -> U71(X1,X2,X3)
          a__U71(tt(),L,N) -> a__U72(a__isNat(N),L)
          a__U72(X1,X2) -> U72(X1,X2)
          a__U72(tt(),L) -> s(a__length(mark(L)))
          a__U81(X) -> U81(X)
          a__U81(tt()) -> nil()
          a__U91(X1,X2,X3,X4) -> U91(X1,X2,X3,X4)
          a__U91(tt(),IL,M,N) -> a__U92(a__isNat(M),IL,M,N)
          a__U92(X1,X2,X3,X4) -> U92(X1,X2,X3,X4)
          a__U92(tt(),IL,M,N) -> a__U93(a__isNat(N),IL,M,N)
          a__U93(X1,X2,X3,X4) -> U93(X1,X2,X3,X4)
          a__U93(tt(),IL,M,N) -> cons(mark(N),take(M,IL))
          a__isNat(X) -> isNat(X)
          a__isNat(0()) -> tt()
          a__isNat(length(V1)) -> a__U11(a__isNatList(V1))
          a__isNat(s(V1)) -> a__U21(a__isNat(V1))
          a__isNatIList(V) -> a__U31(a__isNatList(V))
          a__isNatIList(X) -> isNatIList(X)
          a__isNatIList(cons(V1,V2)) -> a__U41(a__isNat(V1),V2)
          a__isNatIList(zeros()) -> tt()
          a__isNatList(X) -> isNatList(X)
          a__isNatList(cons(V1,V2)) -> a__U51(a__isNat(V1),V2)
          a__isNatList(nil()) -> tt()
          a__isNatList(take(V1,V2)) -> a__U61(a__isNat(V1),V2)
          a__length(X) -> length(X)
          a__length(cons(N,L)) -> a__U71(a__isNatList(L),L,N)
          a__length(nil()) -> 0()
          a__take(X1,X2) -> take(X1,X2)
          a__take(0(),IL) -> a__U81(a__isNatIList(IL))
          a__take(s(M),cons(N,IL)) -> a__U91(a__isNatIList(IL),IL,M,N)
          a__zeros() -> cons(0(),zeros())
          a__zeros() -> zeros()
          mark(0()) -> 0()
          mark(U11(X)) -> a__U11(mark(X))
          mark(U21(X)) -> a__U21(mark(X))
          mark(U31(X)) -> a__U31(mark(X))
          mark(U41(X1,X2)) -> a__U41(mark(X1),X2)
          mark(U42(X)) -> a__U42(mark(X))
          mark(U51(X1,X2)) -> a__U51(mark(X1),X2)
          mark(U52(X)) -> a__U52(mark(X))
          mark(U61(X1,X2)) -> a__U61(mark(X1),X2)
          mark(U62(X)) -> a__U62(mark(X))
          mark(U71(X1,X2,X3)) -> a__U71(mark(X1),X2,X3)
          mark(U72(X1,X2)) -> a__U72(mark(X1),X2)
          mark(U81(X)) -> a__U81(mark(X))
          mark(U91(X1,X2,X3,X4)) -> a__U91(mark(X1),X2,X3,X4)
          mark(U92(X1,X2,X3,X4)) -> a__U92(mark(X1),X2,X3,X4)
          mark(U93(X1,X2,X3,X4)) -> a__U93(mark(X1),X2,X3,X4)
          mark(cons(X1,X2)) -> cons(mark(X1),X2)
          mark(isNat(X)) -> a__isNat(X)
          mark(isNatIList(X)) -> a__isNatIList(X)
          mark(isNatList(X)) -> a__isNatList(X)
          mark(length(X)) -> a__length(mark(X))
          mark(nil()) -> nil()
          mark(s(X)) -> s(mark(X))
          mark(take(X1,X2)) -> a__take(mark(X1),mark(X2))
          mark(tt()) -> tt()
          mark(zeros()) -> a__zeros()
      - Signature:
          {a__U11/1,a__U21/1,a__U31/1,a__U41/2,a__U42/1,a__U51/2,a__U52/1,a__U61/2,a__U62/1,a__U71/3,a__U72/2,a__U81/1
          ,a__U91/4,a__U92/4,a__U93/4,a__isNat/1,a__isNatIList/1,a__isNatList/1,a__length/1,a__take/2,a__zeros/0
          ,mark/1} / {0/0,U11/1,U21/1,U31/1,U41/2,U42/1,U51/2,U52/1,U61/2,U62/1,U71/3,U72/2,U81/1,U91/4,U92/4,U93/4
          ,cons/2,isNat/1,isNatIList/1,isNatList/1,length/1,nil/0,s/1,take/2,tt/0,zeros/0}
      - Obligation:
          innermost runtime complexity wrt. defined symbols {a__U11,a__U21,a__U31,a__U41,a__U42,a__U51,a__U52,a__U61
          ,a__U62,a__U71,a__U72,a__U81,a__U91,a__U92,a__U93,a__isNat,a__isNatIList,a__isNatList,a__length,a__take
          ,a__zeros,mark} and constructors {0,U11,U21,U31,U41,U42,U51,U52,U61,U62,U71,U72,U81,U91,U92,U93,cons,isNat
          ,isNatIList,isNatList,length,nil,s,take,tt,zeros}
  + Applied Processor:
      NaturalPI {shape = Mixed 3, restrict = NoRestrict, uargs = UArgs, urules = URules, selector = Nothing}
  + Details:
      Incompatible
MAYBE