#include <stdio.h>

int main(void){
    double a[2],b[2],c[2],d[2];
    for(;~scanf("%lf %lf %lf %lf %lf %lf %lf %lf",&a[0],&a[1],&b[0],&b[1],&c[0],&c[1],&d[0],&d[1]);){
        if(!((b[0]-a[0])*(d[0]-c[0])+(b[1]-a[1])*(d[1]-c[1])))
            puts("YES");
        else
            puts("NO");
    }
    return 0;
}