#include<cstdio>
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 Ax = bx - ax, Ay = by - ay;
        double Bx = dx - cx, By = dy - cy;
        Ax * Bx + Ay * By == 0 ? puts("YES") : puts("NO");
    }
    return 0;
}