#include <iostream>
#include <vector>
#include <algorithm>
#include <cstdio>
#include <string>
#include <map>


#define rep(x,to) for(int x=0;x<to;x++)
#define rep2(x,from,to) for(int x=from;x<to;x++)

using namespace std;


int main(void){

double x1,y1,x2,y2,x3,y3,x4,y4;
	while(!cin.eof()){
		cin >> x1 >> y1 >> x2 >> y2;
		cin >> x3 >> y3 >> x4 >> y4;
		if( cin.eof()  ) break;
		
		double tc=(x2-x1)*(x4-x3)+(y2-y1)*(y4-y3);
		
		cout << (tc== 0.0 ? "YES": "NO") << endl;
//		printf("%f\n",tc);
	}
	return 0;
	
	
}