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-- File: base64.hs --
import Data.Char
import Text.Printf
import qualified Data.List as L
import qualified Data.List.Split as T
toBase64 x = maskBase64 x . toBase64core . asciiToBin . binFill $ x
toBase64core = map base64toDigit . map binToDec . T.chunksOf 6
base64toDigit x = (['A'..'Z']++['a'..'z']++['0'..'9']++['+','/']) !! x
binToDec = sum . map (2^) . L.findIndices (=='1') . reverse
asciiToBin = concat . map (\y -> printf "%08b" y) . map ord
binFill x = x ++ (take (fill64length x) $ cycle "\000")
maskBase64 o x = take (length x - l ) x ++ (take l $ cycle "=")
where l = (fill64length o)
fill64length x | m==0 = 0
| otherwise = 3-m
where m=mod (length x) 3
main = do
line <- getLine
putStrLn $ toBase64 line
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