((#if:(({1|))}
   |((#if:(({2|))}
      |((#ifexpr:(({1))}>(({2))}
         |((#expr:(({1))}*0.5 round0))km
         |((#expr:(({2))}*0.5 round0))km))
      |((#expr:(({1))}*0.5 round0))km))
   |((#if:(({2|))}
      |((#expr:(({2))}*0.5 round0))km 
      |((#if:(({3|))}|((#expr:exp(0.5*ln((({3))})-0.023) round0))km )) )) ))