Please help me in explaining why this is not collision resistant, and explain a distinguisher attack that would find a collision. Thank you, I will rate!

2. Show that the CBC-MAC construction applied to a PRP is not collision-resistant. More precisely, let F be a secure PRP. Show how to efficiently find collisions in the following salted hash function H : Here we are interpreting k as the salt. This is yet another example of how collisionresistance is different than authenticity (MAC)