#include<cstdio>
#include<cmath>
#include<cstring>
#include<algorithm>
using namespace std;
int main(){
  double x1,y1,x2,y2,x3,y3,x4,y4;
  while(~scanf("%lf %lf %lf %lf %lf %lf %lf %lf",
	      &x1,&y1,&x2,&y2,&x3,&y3,&x4,&y4)){
    if( (x2-x1)*(x4-x3) + (y2-y1)*(y4-y3) == 0 ) printf("YES\n");
    else printf("NO\n");
  }
}