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

int n, i, j, k, arr[100001];
string s, s1, s2;
int main()

{
    bool h = true, v = true;
    cin >> n;
    n = n-1;
    int i1, j1;
    cin >> i1 >> j1;
    while(n--)
    {
        cin >> i >> j;
        if(i != i1)
            h = false;
        if(j != j1)
            v = false;
    }
    if(h or v) cout << "YES";
    else cout <<"NO";
    return 0;
}