#include<cstdio>
using namespace std;
int main() {
    double a,b,c,d,e,f,g,h;
    while(~scanf("%lf%lf%lf%lf%lf%lf%lf%lf", &a,&b,&c,&d,&e,&f,&g,&h)) {
        double Ax = c - a, Ay = d - b;
        double Bx = g - e, By = h - f;
        Ax * Bx + Ay * By == 0 ? puts("YES") : puts("NO");
    }
    return 0;
}