import Control.Monad (replicateM)

solve :: [[Int]] -> Int
solve ab = minimum $ map abs $ f 0 ab

f :: Int -> [[Int]] -> [Int]
f k [] = [k]
f k ab = left ++ right where
    left = f (k + head (head ab)) (tail ab)
    right = f (k - last (head ab)) (tail ab)

main = do
    n <- readLn :: IO Int
    ab <- map (map read . words) <$> replicateM n getLine :: IO [[Int]]
    print $ solve ab