main = do
  n <- readLn
  [c,v] <- map read . words <$> getLine
  print (report n c v)

report n c v = go n c v x0 e0
  where
    x0 = ceiling (logBase 2 (fromIntegral n))
    e0 = maxBound :: Int

go n c v x e
  | x == 0 = e
  | otherwise = go n c v (x - 1) (min e e')
  where
    e' = x * (c + v) + (div1 (max 0 (n - (2^x))) (2^(x-1))) * v

div1 x y = let (q,r) = divMod x y in q + signum r