main = getContents >>= print . solve . map (map read . words) . lines

solve :: [[Integer]] -> Integer
solve [[aw, ab], [bw, bb], [c, d]]
	| ab < c = if d - c + ab <= bw then aw + ab + d - c else aw + bw
	| otherwise = if bw <= d then aw + bw else aw + d