#include <iostream>

using namespace std;

int main(){
	int n;
	double x[100],y[100];
	while(cin>>n){
		for(int i=0;i<4;i++){
		cin>>x[i]>>y[i];
		}
		if((y[0]-y[1])/(x[0]-x[1])==(y[2]-y[3])/(x[2]-x[3]))cout<<"YES"<<endl;
		else cout<<"NO"<<endl;
	}
}