astr m n = "A(" ++ m ++ "," ++ n ++ ")" ack' 0 n = (n+1, [astr (show 0) (show n), (show $ n+1)]) ack' m 0 = let (val, ss) = ack' (m-1) 1 in (val, (astr (show m) (show 0)) : ss) ack' m n = let (val1, ss1) = ack' m (n-1) (val2, ss2) = ack' (m-1) val1 ss = [astr (show $ m-1) s | s <-ss1] ++ (tail ss2) in (val2, (astr (show m) (show n)):ss) ack m n = map (++"\n") $ snd $ ack' m n
main = do [x,y]<-(return.(map read).words)=<<getLine mapM_ putStr $ ack x y
