#include <map>
#include <set>
#include <list>
#include <cmath>
#include <ctime>
#include <deque>
#include <queue>
#include <stack>
#include <string>
#include <bitset>
#include <cstdio>
#include <limits>
#include <vector>
#include <climits>
#include <cstring>
#include <cstdlib>
#include <fstream>
#include <numeric>
#include <sstream>
#include <iostream>
#include <algorithm>
#include <unordered_map>

using namespace std;


int main(){

	long long n, a0, x, y, a, b;
	int first = 1, second = 1;
	cin >> n;
	for (a0 = 0; a0 < n; a0++) {
		cin >> x >> y;
		if (a0 == 0) {
			a = x;
			b = y;
		} else {
			if (a != x)
				first = 0;
			if (b != y)
				second = 0;
		}
	}
	if (first == 1 || second == 1)
		cout << "YES\n";
	else
		cout << "NO\n";
	return 0;

}