The OP asks, "Anyway, if i wanted to buy every Nikon 35mm, how many would i have to buy?"
I probably could arrive at an accurate number, but I don't feel like it. Instead, I'll do as others are doing, and mention those Nikons that I have bothered to accumulate for my own collection. In no particular order:
Nikon F, originally with non-metered prism finder. Later I bought the original non-TTL Photomic head for it. Why? Because I think it looks cool.
Nikon F2, originally with non-metered DE-1 finder. Later, I bought the DP-1 finder for it (F2 Photomic).
Nikon F2 Photomic S. Makes the camera look top-heavy. First F2 with LED meter readout, first F2 that meters down to 10 seconds.
Nikkormat FT3 Latest and greatest mechanical Nikkormat
Nikon EL-2: Version 2 of the Nikkormat EL, basically an FE heavyweight. Functionally the equivalent to the FE, just much more massively built.
Nikon F3 HP I've always thought the F3 was a very elegant, very sexy camera. The meter readout basically sux though.
Nikon F4S Big and heavy, yet still feels good in my hands.
Nikon FE Great Av camera, love the match-needle metering. Can still use pre-AI lenses
Nikon FE2 Ditto above but with 1/4000 sec top shutter speed, 1/250 flash sync, but can't use pre-AI lenses
Nikon FG Under-rated little camera, extremely accurate shutter.
Nikon N80 A very lightweight and very excellent and very cheap camera.
Incidentally, I come up with 51 Nikon 35mm interchangeable lens cameras.