import Control.Monad
import Text.Printf

main :: IO ()
main = do
  t <- readLn
  forM_ [(1::Int)..t] $ \i -> do
    [a,b] <- liftM (map read . words) getLine
    ps <- liftM (map read . words) getLine
    let ans = solve b ps
    printf "Case #%d: %f\n" i ans

solve :: Int -> [Double] -> Double
solve b ps = minimum $ opt3 : opt2
  where
    opt3 = fromIntegral $ 1 + b + 1
    opt2 = do
      let a = length ps
      n <- [0..a]
      let ps' = reverse $ drop n $ reverse ps
          p' = product [p | p <- ps']
          a' = length ps'
      return $ fromIntegral (n + b - length ps' + 1) + (1 - p') * (fromIntegral b + 1)