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(n__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)
  s(X) -> n__s(X)
  add(X1,X2) -> n__add(X1,X2)
  len(X) -> n__len(X)
  activate(n__fst(X1,X2)) -> fst(activate(X1),activate(X2))
  activate(n__from(X)) -> from(activate(X))
  activate(n__s(X)) -> s(X)
  activate(n__add(X1,X2)) -> add(activate(X1),activate(X2))
  activate(n__len(X)) -> len(activate(X))
  activate(X) -> X

max/plus interpretations on N:

  fst_A(x1,x2) = max{51, 62 + x1, 50 + x2}
  fst#_A(x1,x2) = max{4, 38 + x1, 50 + x2}
  0_A = 0
  0#_A = 48
  nil_A = 52
  nil#_A = 49
  s_A(x1) = max{10, -10 + x1}
  s#_A(x1) = max{24, 2}
  cons_A(x1,x2) = max{0, -45 + x1, -10 + x2}
  cons#_A(x1,x2) = max{3, 24, 5}
  n__fst_A(x1,x2) = max{0, 62 + x1, 50 + x2}
  n__fst#_A(x1,x2) = max{49, 39, 3}
  activate_A(x1) = max{0, x1}
  activate#_A(x1) = max{27, 1 + x1}
  from_A(x1) = max{8, 28 + x1}
  from#_A(x1) = max{28, 18 + x1}
  n__from_A(x1) = max{0, 28 + x1}
  n__from#_A(x1) = max{0, 18 + x1}
  n__s_A(x1) = max{10, -10 + x1}
  n__s#_A(x1) = max{3, 1}
  add_A(x1,x2) = max{39, 19 + x1, 28 + x2}
  add#_A(x1,x2) = max{23, 13 + x1, 28}
  n__add_A(x1,x2) = max{39, 19 + x1, 28 + x2}
  n__add#_A(x1,x2) = max{0, 28, 0}
  len_A(x1) = max{74, 73 + x1}
  len#_A(x1) = max{73, 71 + x1}
  n__len_A(x1) = max{74, 73 + x1}
  n__len#_A(x1) = max{72, 25}

precedence:

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