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#include <iostream>
#include <bits/stdc++.h>
//#pragma GCC optimize("O3")
//#pragma GCC optimize("unroll-loops")

#define mp make_pair
#define pb push_back
#define eb emplace_back
#define x first
#define y second
#define sz(x) (int)x.size()
#define all(x) begin(x), end(x)
#define rall(x) rbegin(x), rend(x)
#define FOR(i,a,b) for (int i = (a); i < (b); i++)
#define RFOR(i,b,a) for (int i = (b) - 1; i >= (a); i--)

using namespace std;

typedef unsigned long long ull;
typedef long long ll;
typedef long double ld;
typedef pair<int, int> pi;
typedef pair<ll, ll> pl;
typedef vector<int> veci;
typedef vector<bool> vecb;
typedef vector<vector<int>> vvi;
typedef vector<vector<bool>> vvb;

const int INF_I = 1e9;
const ll INF_LL = 1e18;
const int MOD = 1000000007;
const double eps = 1e-2;
const double PI = 22./7;

ld len(pl a){
    return sqrt(a.x*a.x + a.y*a.y);
}

int main() {

    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    cout.tie(nullptr);

    int n;
    pl a;
    cin >> n >> a.x >> a.y;
    vector<pl> v(n);
    for (int i = 0; i < n; i++)
        cin >> v[i].x >> v[i].y;
    ld sum = 0;
    for (int i = 0; i < n; i++){
        pl v1 = {v[i].x - a.x, v[i].y - a.y};
        pl v2 = {v[(i+1)%n].x - a.x, v[(i+1)%n].y - a.y};
        ld sin = (v1.x*v2.y-v1.y*v2.x) / len(v1) / len(v2);
        sum += asin(sin);
    }

    if (fabs(sum) <= eps)
        cout << "NO\n";
    else
        cout << "YES\n";

    return 0;
}