main :: IO ()
main = do 
    let result = last (primeFactors 600851475143)
    putStrLn (show result)
main :: IO ()
main = do 
    let result = last (primeFactors 600851475143)
    putStrLn (show result)
main = do 
    let result = last (primeFactors 600851475143)
    putStrLn (show result)