YES

TRS:

  fst(0(),Z) -> nil()
  fst(s(X),cons(Y,Z)) -> cons(Y,n__fst(activate(X),activate(Z)))
  from(X) -> cons(X,n__from(s(X)))
  add(0(),X) -> X
  add(s(X),Y) -> s(n__add(activate(X),Y))
  len(nil()) -> 0()
  len(cons(X,Z)) -> s(n__len(activate(Z)))
  fst(X1,X2) -> n__fst(X1,X2)
  from(X) -> n__from(X)
  add(X1,X2) -> n__add(X1,X2)
  len(X) -> n__len(X)
  activate(n__fst(X1,X2)) -> fst(X1,X2)
  activate(n__from(X)) -> from(X)
  activate(n__add(X1,X2)) -> add(X1,X2)
  activate(n__len(X)) -> len(X)
  activate(X) -> X

max/plus interpretations on N:

  fst_A(x1,x2) = max{33, 20 + x1, 23 + x2}
  fst#_A(x1,x2) = max{33, 20 + x1, 23 + x2}
  0_A = 1
  0#_A = 1
  nil_A = 0
  nil#_A = 0
  s_A(x1) = max{5, 4 + x1}
  s#_A(x1) = max{5, 4 + x1}
  cons_A(x1,x2) = max{28, 27 + x1, 4 + x2}
  cons#_A(x1,x2) = max{28, 27 + x1, 4 + x2}
  n__fst_A(x1,x2) = max{19, 6 + x1, 9 + x2}
  n__fst#_A(x1,x2) = max{19, 6 + x1, 9 + x2}
  activate_A(x1) = max{26, 14 + x1}
  activate#_A(x1) = max{26, 14 + x1}
  from_A(x1) = max{25, 28 + x1}
  from#_A(x1) = max{25, 28 + x1}
  n__from_A(x1) = max{24, 19 + x1}
  n__from#_A(x1) = max{24, 19 + x1}
  add_A(x1,x2) = max{44, 23 + x1, 34 + x2}
  add#_A(x1,x2) = max{44, 23 + x1, 34 + x2}
  n__add_A(x1,x2) = max{29, 9 + x1, 30 + x2}
  n__add#_A(x1,x2) = max{29, 9 + x1, 30 + x2}
  len_A(x1) = max{43, 32 + x1}
  len#_A(x1) = max{43, 32 + x1}
  n__len_A(x1) = max{29, 18 + x1}
  n__len#_A(x1) = max{29, 18 + x1}

precedence:

  0 > nil > fst = activate = n__from = len > n__fst = from = add > cons = n__add > s = n__len