YES
O(n^5)
TRS:
 {
   f(a(), a()) -> f(a(), b()),
   f(a(), b()) -> f(s(a()), c()),
  f(s(X), c()) -> f(X, c()),
   f(c(), c()) -> f(a(), a())
 }
 DUP: We consider a non-duplicating system.
  Trs:
   {
     f(a(), a()) -> f(a(), b()),
     f(a(), b()) -> f(s(a()), c()),
    f(s(X), c()) -> f(X, c()),
     f(c(), c()) -> f(a(), a())
   }
  Matrix Interpretation:
   Interpretation class: triangular
         [0]
         [2]
   [c] = [0]
         [0]
         [3]
   
       [X4]    [1 2 0 0 0][X4]   [3]
       [X3]    [0 0 0 0 0][X3]   [0]
   [s]([X2]) = [0 0 0 0 0][X2] + [0]
       [X1]    [0 0 0 0 0][X1]   [0]
       [X0]    [0 0 0 0 1][X0]   [0]
   
         [0]
         [0]
   [b] = [0]
         [2]
         [0]
   
         [0]
         [0]
   [a] = [2]
         [0]
         [0]
   
       [X9]  [X4]    [1 2 0 0 1][X9]   [1 0 3 2 0][X4]   [0]
       [X8]  [X3]    [0 0 0 0 1][X8]   [0 0 0 0 0][X3]   [0]
   [f]([X7], [X2]) = [0 0 0 0 3][X7] + [0 0 0 0 0][X2] + [0]
       [X6]  [X1]    [0 0 0 0 0][X6]   [0 0 0 0 0][X1]   [0]
       [X5]  [X0]    [0 0 0 0 0][X5]   [0 0 0 0 0][X0]   [0]
   
   
   Qed