#include<cstdio>
#include<cstdlib>
using namespace std;
int main(){
     
    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 a,b,c,d;
         
        a = (yA-yB);
        b = (xA-xB);
        c = (yC-yD);
        d = (xC-xD);
         
        (a*c + b*d == 0) ? puts("YES") : puts("NO");
    }
     
    return 0;
}