#include<iostream>
#include<string>
using namespace std;
int main(){
	double ax,bx,cx,dx,ay,by,cy,dy;
	while(cin>>ax>>ay>>bx>>by>>cx>>cy>>dx>>dy){
		if((ay-by)*(cy-dy)==-1*(ax-bx)*(cx-dx))
			cout<<"YES"<<endl;
		else
			cout<<"NO"<<endl;
	}
	return 0;
}