ata = []

begin
  while line = $stdin.gets.chomp
    break if line == ""
    data.push(line.split(" "))
  end
rescue
end

data.each{|d|
  d.map!{|elem| elem.to_f }
  delta1 = (d[3] - d[1]) / (d[2] - d[0])
  delta2 = (d[7] - d[5]) / (d[6] - d[4])
  puts (delta1 == delta2) ? "NO" : "YES"
}