#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
using namespace std;


int main() {
    int N, flag = 0, x, y, i ;
    vector<int> X, Y;
    
    cin >> N;
    while(N--) {
        cin >> x >> y;
        X.push_back(x);
        Y.push_back(y);
    }
    int flagx = 0, flagy = 0;
    for(i = 1; i < X.size(); i++) {
        if(X[i] != X[i-1]) {
            flagx = 1;
        }
        if(Y[i] != Y[i-1])
            flagy = 1;
    }
    
    if(flagx && flagy) {
        cout << "NO";
    }
    else
        cout << "YES";
    return 0;
}