//is a point inside a convex polygon? | https://informatics.mccme.ru/mod/statements/view3.php?id=41131&chapterid=451
//Made by @maximihajlov | PhTS2020a | 30/05/2019


import java.util.Scanner;

public class TaskD {
    public static class Point {
        public Point(double x0, double y0) {
            x = x0;
            y = y0;
        }

        double x;
        double y;
    }

    public static int N;
    public static Point Poly[];

    public static boolean solve(Point spot) {
        int i;
        int j;
        boolean ans = false;
        for (i = 0, j = Poly.length - 1; i < Poly.length; j = i++) {
            if ((Poly[i].y > spot.y) != (Poly[j].y > spot.y) &&
                    (spot.x < (Poly[j].x - Poly[i].x) * (spot.y - Poly[i].y) / (Poly[j].y - Poly[i].y) + Poly[i].x)) {
                ans = !ans;
            }
        }
        return ans;
    }

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        N = sc.nextInt();

        Poly = new Point[N];

        for (int i = 0; i < N; i++) Poly[i] = new Point(sc.nextDouble(), sc.nextDouble()); //Polygon input

        Point spot = new Point(sc.nextDouble(), sc.nextDouble());//xPoint

        if (solve(spot)) System.out.println("YES");
        else System.out.println("NO");
    }

}