main = getLine >>= print . waza . map read . words

waza [h,a,d] = minimum $ do
 na <- [0 .. ceiling (fromIntegral h / fromIntegral a)]
 let nd = ceiling $ fromIntegral (max (h-a*na) 0) / fromIntegral d
 return (fromIntegral na + (fromIntegral nd) * (3/2))