sumDigits :: [Integer] -> Integer
sumDigits xs = foldr (\x y -> y + sum  (toDigits x)) 0 xs
sumDigits :: [Integer] -> Integer
sumDigits xs = foldr (\x y -> y + sum  (toDigits x)) 0 xs
sumDigits xs = foldr (\x y -> y + sum  (toDigits x)) 0 xs