#include <bits/stdc++.h>

const int Maxn = 1e5 + 3;

using namespace std;

int n, x, y, X, Y, F1, F2;

int main()
{

    //freopen("in", "r", stdin);
    F1 = F2 = 1;

    cin >> n;

    cin >> x >> y;

    for (int i = 2; i <= n; i++)
    {
        cin >> X >> Y;
        if (X != x) F1 = 0;
        if (Y != y) F2 = 0;
    }

    if (F1 || F2)
        puts("YES");
    else
        puts("NO");

}