judge :: [String] -> String
judge (sa : pa : sb : pb : _)
    | pa' > pb'   = sa
    | pb' > pa'   = sb
    | otherwise = "-1"
    where
        pa' = read pa :: Integer
        pb' = read pb :: Integer

main :: IO ()
main = putStrLn . judge . concat . map (take 2) . map words . lines =<< getContents