#include <bits/stdc++.h>
using namespace std;

typedef long long int ll;
typedef unsigned long long int ull;
typedef vector<ll> vi;
typedef vector<vi> vvi;
typedef pair<ll, ll> pi;
typedef pair<char, ll> pci;
typedef vector<pi> vii;
typedef map<ll, ll> mi;
typedef set<ll> seti;

#define sz size()
#define ins insert
#define mp make_pair
#define pb push_back
#define nl << "\n";
#define all(x) x.begin(), x.end()
#define db(x) cout << #x << " = " << x nl
#define input(x) for (auto &a : x) cin >> a;
#define view(x) cout << #x << ": "; for (auto a : x) {cout << a << " ";} cout nl
#define viewp(x) cout << #x << ": "; for (auto &a : x) {cout << a.first << " " << a.second nl}

void solve() {
    ll n;
    cin >> n;
    vi a(n + 1), b(n + 1);
    for (int i = 0; i < n; i++) {
        cin >> a[i];
        cin >> b[i];
    }
    ll x2, y2;
    cin >> x2 >> y2;
    a[n] = a[0];
    b[n] = b[0];
    long double sum = 0;
    for (ll i = 0, j = 1; i < n, j < n + 1; i++, j++) {
        sum += (a[i] * b[j]);
    }
    for (ll i = 1, j = 0; i < n + 1, j < n; i++, j++) {
        sum -= (a[i] * b[j]);
    }
    sum /= 2.0;
    a[n] = x2;
    b[n] = y2;
    a.pb(a[0]);
    b.pb(b[0]);
    long double sum2 = 0;
    for (ll i = 0, j = 1; i < n + 1, j < n + 2; i++, j++) {
        sum2 += (a[i] * b[j]);
    }
    for (ll i = 1, j = 0; i < n + 2, j < n + 1; i++, j++) {
        sum2 -= (a[i] * b[j]);
    }
    sum2 /= 2.0;
    db(sum)
    db(sum2)
    if (abs(sum2) > abs(sum)) {
        cout << "NO" nl
    } else {
        cout << "YES" nl
    }
}

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    cout.tie(nullptr);
    ll t = 1;
    //cin >> t;
    while (t--) {
        solve();
    }
    return 0;
}