#include <iostream>
#include <fstream>
#include <vector>
#include <queue>
#include <utility>
#include <algorithm>
#include <functional>
#include <string>
#include <cstring>
#include <cmath>
#include <map>
#include <set>
#include <stack>
#include <iomanip>
#define NMAX 200005
#define INF 0x3f3f3f3f
#define pb push_back

using namespace std;

typedef pair<int, int> pii;

//ifstream fin("calafat.in");
//ofstream fout("calafat.out");

set<int> lin, col;

int main() {
	int n,i,m,j,x,y;

	cin>>n;
	for(i=0;i<n;++i) {
		cin>>x>>y;
		lin.insert(x);
		col.insert(y);
	}
	
	if(lin.size()==1 || col.size() == 1) cout<<"YES";
	else cout<<"NO";

	return 0;
}