while str = STDIN.gets
	if str == -1 then break end

	a = str.split(' ');
	eps = 1e-12;
	for i in 0...8 do
		a[i] = a[i].to_f
	end

	if ((a[0]-a[2])*(a[4]-a[6])+(a[1]-a[3])*(a[5]-a[7])).abs <= eps then
		puts "YES\n" 
	else
		puts "NO\n"
	end

end