import std.stdio;
import std.string;
import std.conv;
import std.algorithm;
import std.math;



void main() {
    immutable EPS = 1.0e-12;
    string[] input = new string[](8);

    while ((input = readln.chomp.split(" ")).length != 0) {
        auto points = input.map!(to!double);
        auto innerProduct = fabs((points[2] - points[0])*(points[6] - points[4]) + (points[3] - points[1])*(points[7] - points[5]));

        if (innerProduct < EPS) {
            writeln("YES");
        } else {
            writeln("NO");
        }
    }
}