#include <iostream>
#include <set>
typedef long long ll;
using namespace std;
set<int>a , b;
int main() {
int n,x,y;
cin >> n;
for(int i = 0; i < n; i ++) {

    cin >> x >> y;
    a.insert(x);
    b.insert(y);
}
if(a.size() == 1 || b.size() == 1) cout<<"YES"<<endl;
else cout<<"NO"<<endl;
return 0;
}