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

struct Point {
    int x, y;
};

// Function to check if a point is strictly inside a polygon
bool isPointInsidePolygon(const vector<Point>& polygon, Point p) {
    int n = polygon.size();
    bool inside = false;

    for (int i = 0, j = n - 1; i < n; j = i++) {
        // Check if the point lies within the y-bounds of the edge
        if ((polygon[i].y > p.y) != (polygon[j].y > p.y)) {
            // Check if the ray crosses the edge
            double intersectionX = polygon[j].x + (p.y - polygon[j].y) * 1.0 * (polygon[i].x - polygon[j].x) / (polygon[i].y - polygon[j].y);
            if (p.x < intersectionX) {
                inside = !inside;
            }
        }
    }

    return inside;
}

int main() {
    int n;
    cin >> n;

    vector<Point> polygon(n);
    for (int i = 0; i < n; i++) {
        cin >> polygon[i].x >> polygon[i].y;
    }

    Point p;
    cin >> p.x >> p.y;

    if (isPointInsidePolygon(polygon, p)) {
        cout << "YES" << endl;
    } else {
        cout << "NO" << endl;
    }

    return 0;
}