import std.stdio,std.string,std.conv,std.math;

int main()
{
	double EPS = 1e-12;
	string s;
	while((s = readln.chomp).length != 0)
	{
		string[] _s = s.split(" ");
		double a[8];
		foreach(i;0..8)
		{
			a[i] = _s[i].to!double;
		}

		if(fabs(((a[2]-a[0])*(a[6]-a[4]))+((a[3]-a[1])*(a[7]-a[5]))) <= EPS)
		{
			writeln("YES");
		}
		else 
		{
			writeln("NO");
		}
	}
	return 0;
}