#include <iostream>

using namespace std;

int main(){
        double x[8];
        while(cin >> x[0]){
                for(int i = 1; i < 8; i++) cin >> x[i];
                if((x[0]-x[2])*(x[4]-x[6])+(x[1]-x[3])*(x[5]-x[7])) cout << "NO" << endl;
                else cout << "YES" << endl;
        }   
}