YES
Input TRS:
      1: f(x1) -> n(c(n(a(x1))))
      2: c(f(x1)) -> f(n(a(c(x1))))
      3: n(a(x1)) -> c(x1)
      4: c(c(x1)) -> c(x1)
      5: n(s(x1)) -> f(s(s(x1)))
      6: n(f(x1)) -> f(n(x1))
Number of strict rules: 6
Direct POLO(bPol) ... failed.
Uncurrying ... failed.
Dependency Pairs:
     #1: #c(f(x1)) -> #f(n(a(c(x1))))
     #2: #c(f(x1)) -> #n(a(c(x1)))
     #3: #c(f(x1)) -> #c(x1)
     #4: #n(f(x1)) -> #f(n(x1))
     #5: #n(f(x1)) -> #n(x1)
     #6: #n(s(x1)) -> #f(s(s(x1)))
     #7: #n(a(x1)) -> #c(x1)
     #8: #f(x1) -> #n(c(n(a(x1))))
     #9: #f(x1) -> #c(n(a(x1)))
     #10: #f(x1) -> #n(a(x1))
Number of SCCs: 1, DPs: 10
  SCC { #1..10 }
POLO(Sum)... succeeded.
      a 	w: 0
      s 	w: 21239
      n 	w: x1
      c 	w: 0
      f 	w: x1
      #f 	w: 0
      #c 	w: 0
      #n 	w: x1
    USABLE RULES: { 1..6 }
    Removed DPs: #6
Number of SCCs: 1, DPs: 9
  SCC { #1..5 #7..10 }
POLO(Sum)... POLO(max)... QLPOS... POLO(mSum)... QWPOpS(mSum)... Mat2b... succeeded.
      a 	w: [0,0;0,1] * x1
      s 	w: [4635;27742]
      n 	w: [1,0;1,1] * x1
      c 	w: [0,0;0,1] * x1
      f 	w: x1 + [0;4635]
      #f 	w: [0,1;0,0] * x1 + [2;0]
      #c 	w: [0,1;0,0] * x1
      #n 	w: [1,1;0,0] * x1 + [1;0]
    USABLE RULES: { 1..6 }
    Removed DPs: #1..5 #7..10
Number of SCCs: 0, DPs: 0