require "matrix"

EPS = 1e-10

while line = gets
  xa, ya, xb, yb, xc, yc, xd, yd = line.split.map(&:to_f)
  vab, vcd = Vector[xb - xa, yb - ya], Vector[xd - xc, yd - yc]
  
  puts vab.inner_product(vcd).floor == 0 ? "YES" : "NO"
end