Consider the TRS R consisting of the rewrite rules

1: d(x) -> e(u(x))
2: d(u(x)) -> c(x)
3: c(u(x)) -> b(x)
4: v(e(x)) -> x
5: b(u(x)) -> a(e(x))

There are 2 dependency pairs:

6: D(u(x)) -> C(x)
7: C(u(x)) -> B(x)

The approximated dependency graph contains no SCCs
and hence the TRS is trivially terminating.