Consider the TRS R consisting of the rewrite rule

1: f(g(f(a),h(a,f(a)))) -> f(h(g(f(a),a),g(f(a),f(a))))

There is one dependency pair:

2: F(g(f(a),h(a,f(a)))) -> F(h(g(f(a),a),g(f(a),f(a))))

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