#include<iostream>
#include<string>
using namespace std;

double x[4],y[4];
string judge ();

int main() {
	while ( cin >> x[0] ) {
		for( int i = 0; i < 4; i++ ){
			if ( !i )
				cin >> y[i];
			else
				cin >> x[i] >> y[i];
		}
		
		cout <<  judge () << endl;
		
	}
	return 0;
}

string judge () {
	string res;
	double a,b;
	int n,nn;
	
	for ( int i = 0; i < 3; i++ ) {
		if ( i == 2 ){
			n = '0';
			nn = n + 1;
		}else if ( i == 1 ){
			n = i + 1;
			nn = '0';
		}else{
			n = i + 1;
			nn = n + 1;
		}
		
		if ( x[n] != x[i] ){
			a = (y[n] - y[i]) / (x[n] - x[i]);
			b = (x[i] * y[n] - x[n] * y[i]) / (x[i] - x[n]);
			
			if ( (a * x[3] + b) > y[3] && (a * x[nn] + b) < y[nn] || (a * x[3] + b) < y[3] && (a * x[nn] + b) > y[nn] ) {
				return "NO";
			}
		} else {
			
			if ( x[3] < x[i] && x[nn] > x[i] || x[3] > x[i] && x[nn] < x[i] )
				return "NO";
		}
		
	}
	return "YES";
	
}