main = do
  s <- getContents
  let v = map (map read . words) . lines $ s
  let w = map solve v
  let x = map (\x-> if x then "YES" else "NO") $ w
  mapM_ putStrLn x

solve::[Double] -> Bool
solve [xa,ya,xb,yb,xc,yc,xd,yd] =
  dot u v == 0.0
  where u = (xb-xa, yb-ya)
        v = (xd-xc, yd-yc)
        dot (a,b) (c,d) = a*c + b*d