MAYBE
Input TRS:
      1: b(b(b(x1))) -> a(a(a(x1)))
      2: a(a(a(x1))) -> b(a(b(x1)))
Number of strict rules: 2
Direct POLO(bPol) ... failed.
Uncurrying ... failed.
Dependency Pairs:
     #1: #a(a(a(x1))) -> #b(a(b(x1)))
     #2: #a(a(a(x1))) -> #a(b(x1))
     #3: #a(a(a(x1))) -> #b(x1)
     #4: #b(b(b(x1))) -> #a(a(a(x1)))
     #5: #b(b(b(x1))) -> #a(a(x1))
     #6: #b(b(b(x1))) -> #a(x1)
Number of SCCs: 1, DPs: 6
  SCC { #1..6 }
POLO(Sum)... succeeded.
      a 	w: x1 + 2438
      b 	w: x1 + 2438
      #a 	w: x1
      #b 	w: x1
    USABLE RULES: { 1 2 }
    Removed DPs: #2 #3 #5 #6
Number of SCCs: 1, DPs: 2
  SCC { #1 #4 }
POLO(Sum)... POLO(max)... QLPOS... POLO(mSum)... QWPOpS(mSum)... Mat2b... failed.
Finding a loop...  failed.