#include <cstdio>
using namespace std;

int main(){
	double X[4], Y[4];
	double AB[2], CD[2];
	
	while(scanf("%lf%lf%lf%lf%lf%lf%lf%lf",X+0,Y+0,X+1,Y+1,X+2,Y+2,X+3,Y+3) != EOF){
		AB[0] = X[1] - X[0];
		AB[1] = Y[1] - Y[0];
		CD[0] = X[3] - X[2];
		CD[1] = Y[3] - Y[2];
		
		if(AB[0] * CD[0] + AB[1] * CD[1] == 0) printf("YES\n");
		else printf("NO\n");
	}
	
	return 0;
}