#include <stdio.h>

int main(void){
	double x1, x2, x3, x4, y1, y2, y3, y4;
	double a1, a2;

	while(scanf("%lf %lf %lf %lf %lf %lf %lf %lf", &x1, &y1, &x2, &y2, &x3, &y3, &x4, &y4) != EOF){
		if(y2-y1 == 0 && y4 - y3 == 0){
			printf("NO\n");
		}else if(x2-x1 != 0 && x4-x3 != 0){
			a1 = (y2 - y1) / (x2 - x1);
			a2 = (y4 - y3) / (x4 - x3);
			if(a1 == -a2) printf("YES\n");
			else printf("NO\n");
		}else if(x2 - x1 == 0 && x4 - x3 == 0){
			printf("NO\n");
		}else if(x2 - x1 == 0){
			a2 = (y4 - y3) / (x4 - x3);
			if(a2 == 0) printf("YES\n");
			else printf("NO\n");
		}else{
			a1 = (y2 - y1) / (x2 - x1);
			if(a1 == 0) printf("YES\n");
			else printf("NO\n");
		}
	}

	return 0;
}