#include <stdio.h>

struct Point {
    int x, y;
};

int isInside(struct Point polygon[], int n, struct Point p) {
    int count = 0, i, next;
    for (i = 0; i < n; i++) {
        next = (i + 1) % n;
        if (p.y > polygon[i].y && p.y <= polygon[next].y || p.y > polygon[next].y && p.y <= polygon[i].y) {
            if (p.x <= (polygon[next].x - polygon[i].x) * (p.y - polygon[i].y) / (polygon[next].y - polygon[i].y) + polygon[i].x)
                count++;
        }
    }
    return count % 2;
}

int main() {
    int n, i;
    struct Point polygon[1000], p;

    scanf("%d", &n);
    for (i = 0; i < n; i++) {
        scanf("%d %d", &polygon[i].x, &polygon[i].y);
    }
    scanf("%d %d", &p.x, &p.y);

    if (isInside(polygon, n, p))
        printf("YES\n");
    else
        printf("NO\n");

    return 0;
}