So, I'm about as un-program/logic minded as you can get, as proved by the fact that I got THIS FAR
Main, ^<vF^<v^F??, function as in PDA
on the multiple-solution monster .viR mentioned above before giving that road up as impossible and trying several completely nonsensical ones, because I somehow made the arbitrary and obviously false decision that the path that seemed most promising was a dead end. So much so that I had to look up the solutions, and saw mine staring at me with the obvious addition completing it. I even considered that very option, thinking EUREKA! but after attempting to 'run' it in my head dismissed it as so obviously flawed that I didn't even bother punching it in.
I think it's time I gave up attempting to learn even C++.