#include <bits/stdc++.h>
using namespace std;
int main()
{
    int n;
    cin >> n;
    int maxi_x(0), maxi_y(0);
    while (n--)
    {
        int x, u;
        cin >> x >> u;
        maxi_x = max(maxi_x, x);
        maxi_y = max(maxi_y, u);
    }
    int l, k;
    cin >> l >> k;
    if (l > maxi_x || k > maxi_y)
    {
        cout << "NO";
    }
    else
    {
        cout << "YES";
    }
}