import Control.Monad (when)
import Data.List ((\\), intercalate)
import Data.Maybe (catMaybes, isNothing)
-import Data.String.Utils (splitWs)
import System.Exit (ExitCode( ExitFailure ), exitWith)
import System.IO (stderr, hPutStrLn)
import Text.Read (readMaybe)
-- This reads stdin.
input <- getContents
- let cidr_strings = splitWs input
+ let cidr_strings = words input
let cidrs = map readMaybe cidr_strings :: [Maybe Cidr]
when (any isNothing cidrs) $ do