#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){
      if(y4==y3) puts("YES");
      else puts("NO");
    } else if(x4==x3){
      if(y2==y1) puts("YES");
      else puts("NO");
    } else{
      if(((y2-y1)/(x2-x1))*((y4-y3)/(x4-x3))==-1) puts("YES");
      else puts("NO");
    }
  }
}