f :: Float -> Float -> Float -> Float
--f a b x = (if x >= a * a * b / 2 then atan (2*a*b-2*x/a) else atan (a*b*b/(2*x)))*180/pi
f a b x = (if x >= a * a * b / 2 then atan ((2*b/a)-(2*x/(a*a*a))) else atan (a*b*b/(2*x)))*180/pi
main = do
    [a,b,x] <- getLine >>= return . (map (read :: String -> Float)) . words
    putStrLn $ show $ if x == a * a * b then 0 else f a b x