#include <iostream>
#include <vector>
#include <string>
#include <stack>
#include <queue>
#include <deque>
#include <set>
#include <map>
#include <algorithm>	// require sort next_permutation count __gcd reverse etc.
#include <cstdlib>	// require abs exit atof atoi 
#include <cstdio>		// require scanf printf
#include <functional>
#include <numeric>	// require accumulate
#include <cmath>		// require fabs
#include <climits>
#include <limits>
#include <cfloat>
#include <iomanip>	// require setw
#include <sstream>	// require stringstream 
#include <cstring>	// require memset
#include <cctype>		// require tolower, toupper
#include <fstream>	// require freopen
#include <ctime>		// require srand
#define rep(i,n) for(int i=0;i<(n);i++)
#define ALL(A) A.begin(), A.end()
#define EPS 1e-8

using namespace std;

typedef long long ll;
typedef pair<int, int> P;

double dot (double x1, double y1, double x2, double y2 )
{
	return (x1*x2 + y1*y2 );
}

int main()
{
//	cut here before submit 
//	freopen ("testcase.orthogonal", "r", stdin );
	double xA, yA, xB, yB, xC, yC, xD, yD;

	while (scanf ("%lf %lf %lf %lf %lf %lf %lf %lf", &xA, &yA, &xB, &yB, &xC, &yC, &xD, &yD ) != EOF ){
		double ax = xB - xA, ay = yB - yA;
		double bx = xD - xC, by = yD - yC;
		if (fabs (dot (ax, ay, bx, by ) ) < EPS ){
			printf ("YES\n" );
		}else{
			printf ("NO\n" );
		} // end if
	} // end loop
		
	return 0;
}