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


int main() {
    /* Enter your code here. Read input from STDIN. Print output to STDOUT */ 
    int x, y, k, nl;
    cin >> nl;
    int xy[nl][2];
    x=y=1;
    for(k=0; k<nl; k++){
        cin >> xy[k][0] >> xy[k][1];
    }
    for(k=0; k<nl-1; k++){
       if(xy[k][0] != xy[k+1][0])
               x =0;
        }
    if(x == 1)
        cout << "YES" << endl;
    else{
     for(k=0; k<nl-1; k++){
           if(xy[k][1] != xy[k+1][1])
               y =0;
        }
      if(y == 1)  
          cout << "YES" << endl;
    else
    cout << "NO" << endl;
    }
    return 0;
}