Problem:
Score : 300 points

Problem Statement

Compute A \times B, truncate its fractional part, and print the result as an integer.

Constraints

0 \leq A \leq 10^{15}

0 \leq B < 10

A is an integer.

B is a number with two digits after the decimal point.

Input

Input is given from Standard Input in the following format:

A B

Output

Print the answer as an integer.

Sample Input 1

198 1.10

Sample Output 1

217

We have 198 \times 1.10 = 217.8. After truncating the fractional part, we have the answer: 217.

Sample Input 2

1 0.01

Sample Output 2

0

Sample Input 3

1000000000000000 9.99

Sample Output 3

9990000000000000

Solution in Haskell (GHC 8.8.3) (judge verdict: Accepted)

{-# LANGUAGE TypeApplications #-}
import qualified Data.ByteString.Char8 as BS
import qualified Data.ByteString.Char8 as B
import Data.Maybe
import Data.List
import Control.Monad

toInt :: String -> Int
toInt = read

main :: IO ()
main = do
  l <- words <$> getLine
  let a = toInt $ l !! 0
  let b = toInt $ [x | x <- l !! 1, not (elem x ".")]
  print $ div (a * b) 100