AlmostZERO = 1e-10

def checkOrthogonal(pos)
  ((pos[6] - pos[4]) * (pos[2] - pos[0]) + (pos[7] - pos[5]) * (pos[3] - pos[1])).abs < AlmostZERO
end

while input = $stdin.gets
  if checkOrthogonal(input.chomp.split(" ").map(&:to_f))
    puts "YES"
  else
    puts "NO"
  end
end