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

int X[15],Y[15];

int main() {
    int n;
    cin >> n;
    for(int i = 0 ; i < n ; ++i)    cin >> X[i] >> Y[i];
    bool hor = true;
    bool ver = true;
    for(int i = 1 ; i < n ; ++i) {
        if(X[i] != X[i-1])  ver = false;
        if(Y[i] != Y[i-1])  hor = false;
    }
    if(hor | ver)   puts("YES");
    else puts("NO");
    return 0;
}