YES
Input TRS:
      1: c(c(c(a(x1)))) -> d(d(x1))
      2: d(b(x1)) -> c(c(x1))
      3: c(x1) -> a(a(a(a(x1))))
      4: d(x1) -> b(b(b(b(x1))))
      5: b(d(x1)) -> c(c(x1))
      6: a(c(c(c(x1)))) -> d(d(x1))
Number of strict rules: 6
Direct POLO(bPol) ... removes: 4 1 3 5 6 2
      a 	w: x1 + 16
      d 	w: x1 + 105
      b 	w: x1 + 26
      c 	w: x1 + 65
Number of strict rules: 0