while line = gets
    xa, ya, xb, yb, xc, yc, xd, yd = line.chomp.split.map{|z| (z.to_f * 100000).to_i}
dya = yb-ya
dxa = xb-xa
dyc = yd-yc
dxc = xd-xc
    puts (dya * dyc == -1 * dxa * dxc) ? "YES" : "NO"
#    puts "#{dya * dyc} #{dxa*dxc} #{} "
end

