Totally dissimilar, and I've never understood the argument that a Mach 2.8+ high altitude interceptor is a copy of a Mach 2.2 low-medium altitude light bomber on the grounds of a vaguely similar planform. There are only so many ways to arrange two crew and two engines, high wings are a common enough feature, and twin fins make sense if you don't want a tail fin like the Tornado.Mig 25 [...] A-5 Vigilante
If anything, the Soviets during the early and middle parts of the Cold War were insistent that their designs were ideologically pure to demonstrate the superiority of the Communist economic system. Not only were they not copies of Western equipment, in some cases they actively avoided coming up with the same design as the West so that they couldn't be accused of copying!