main :: IO()
main = do
    str <- getLine
    putStrLn $ getsolve str
    
    
getsolve :: String -> String
getsolve str
    | len == 0			= ""
    | len == 1			= str 
    | len == 2			= [head str]
    | len == 3			= [head str, str!!2]
    | otherwise			= [head str, str!!2] ++ (getsolve (drop 4 str))
    where len = length str