D

#include <iostream>
#include <cmath>
#include <iomanip>

using namespace std;

struct Point {
    double x, y;

    Point(double x0 = 0, double y0 = 0)
    {
        x = x0;
        y = y0;
    }
};

istream & operator >> (istream & in, Point & P) {
    in >> P.x >> P.y;
    return in;
}


struct Vector {
    double x, y;

    Vector(double x0, double y0) {
        x = x0;
        y = y0;
    }

    Vector(Point A, Point B) {
        x = B.x - A.x;
        y = B.y - A.y;
    }
};


double vectMultipl(Vector a, Vector b) {
    return a.x * b.y - b.x * a.y;
}

double scalarMultipl(Vector a, Vector b) {
    return a.x * b.x + b.y * a.y;
}


bool onSegment(Point C, Point A, Point B) {
    Vector AB = Vector(A, B);
    Vector AC = Vector(A, C);
    Vector BA = Vector(B, A);
    Vector BC = Vector(B, C);
    if (vectMultipl(AB, AC) == 0 && AB.x * AC.x >= 0 && AB.y * AC.y >= 0 &&
        vectMultipl(BA, BC) == 0 && BA.x * BC.x >= 0 && BA.y * BC.y >= 0)
        return true;
    else
        return false;
 }


int main() {
    int n;
    Point O;
    cin >> n >> O;
    Point polygon[n];
    for (int i = 0; i < n; i++)
        cin >> polygon[i];
    double angle = 0;
    for (int i = 0; i < n; i++) {
        if (onSegment(O, polygon[i], polygon[(i + 1) % n])) {
            cout << "YES";
            return 0;
        }
        Vector OPi = Vector(O, polygon[i]);
        Vector OPi1 = Vector(O, polygon[(i + 1) % n]);
        angle += atan2(vectMultipl(OPi, OPi1), scalarMultipl(OPi, OPi1));
    }
    if (abs(abs(angle) - 2 * M_PI) <= 0.1)
        cout << "YES";
    else
        cout << "NO";
    return 0;
}