#include<cstdio>
#include<cmath>
using namespace std;
int main() {
    double ax, ay, bx, by, cx, cy, dx, dy;
    while(~scanf("%lf%lf%lf%lf%lf%lf%lf%lf", &ax, &ay, &bx, &by, &cx,&cy,&dx,&dy)) {
        double dot = (ax - bx) * (cx - dx) + (ay - by) * (cy - dy);
        abs(dot) < 1e-10 ? puts("YES") : puts("NO");
    }
    return 0;
}