#include <bits/stdc++.h>
using namespace std;
int n, x[10005], y[10005];

int main() {
    cin >> n;
    bool ok1 = 1, ok2 = 1;
    for(int i = 0; i < n; ++ i) {
        cin >> x[i] >> y[i];
        if(i > 0 && x[i] != x[i - 1]) ok1 = 0;
        if(i > 0 && y[i] != y[i - 1]) ok2 = 0;
    }
    if(ok1 || ok2) cout << "YES";
    else  cout << "NO";
}