Bah!

Now that Public round is over I found a way to equal Rogiers 152
No need to check for / or \ at all 

function a($b)
    dim $c,$,$d
    $=join(split($b,_),$)
    while $
        $d=$c<'/'
        $c=$
        $=right($,~)
        $d=$d+($<'/')
        $a=$a+iif($c>_,$d,2*($c<'/'|($d>)))
    loop
    $a=$a*50/($b^)
endfunction
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