#include <iostream>
#include <string>
using namespace std;

int main(){

	long double xa, ya, xb, yb, xc, yc, xd, yd;

	while (cin >> xa >> ya >> xb >> yb >> xc >> yc >> xd >> yd){
		if ((yb-ya)*(yd-yc) + (xd-xc)*(xb-xa) == 0)
		{
			cout <<"YES"<< endl;
		}
		else
		{
			cout <<"NO"<< endl;
		}

	}
	return 0;
}