import java.util.Scanner;

public class Dot_and_poligon {

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        double arrx[] = new double[n + 1];
        double arry[] = new double[n + 1];
        for (int i = 0; i < n; i++) {
            arrx[i] = sc.nextDouble();
            arry[i] = sc.nextDouble();
        }
        double x = sc.nextDouble();
        double y = sc.nextDouble();
        arrx[n] = arrx[0];
        arry[n] = arry[0];
        int ch = -1;
        for (int i = 0; i < n + 1; i++) {
            double d = arrx[i] * arry[i + 1] - arrx[i + 1] * arry[i] + arrx[i + 1] * y - x * arry[i + 1] + x * arry[i]
                    - arrx[i] * y;
            if (ch == -1) {
                if (d > 0)
                    ch = 1;
                if (d < 0)
                    ch = 0;
            } else {
                if (d < 0 && ch == 1) {
                    ch = 2;
                }
                if (d > 0 && ch == 0) {
                    ch = 2;
                }
            }
        }
        if (ch != 2)
            System.out.println("YES");
        else
            System.out.println("NO");
        sc.close();

    }

}