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

int main(){
	string in;
	double x[4], y[4];
	while(1){
		getline( cin, in );
		if( in.length() == 0 )	return 0;
		sscanf( in.c_str(), "%lf %lf %lf %lf %lf %lf %lf %lf", &x[0], &y[0], &x[1], &y[1], &x[2], &y[2], &x[3], &y[3] );
		double v1[2] = {x[1]-x[0], y[1]-y[0]},
			   v2[2] = {x[3]-x[2], y[3]-y[2]};
		if( v1[0]*v2[0]+v1[1]*v2[1] == 0.0 )
			printf("YES\n");
		else
			printf("NO\n");
	}
	return 0;
}