#include <map>
#include <set>
#include <list>
#include <cmath>
#include <ctime>
#include <deque>
#include <queue>
#include <stack>
#include <string>
#include <bitset>
#include <cstdio>
#include <limits>
#include <vector>
#include <climits>
#include <cstring>
#include <cstdlib>
#include <fstream>
#include <numeric>
#include <sstream>
#include <iostream>
#include <algorithm>
#include <unordered_map>

using namespace std;


int main(){
    int n;
    cin >> n;
    bool hor=true, ver=true;
    int prevx ,prevy;
    cin >> prevx >> prevy;
    for(int a0 = 0; a0 < n-1; a0++){
        int x;
        int y;
        cin >> x >> y;
       if(x != prevx)
           hor= false;
       if(y != prevy)
          ver= false;
       prevx = x;
        prevy = y;
      
    }
    if(hor || ver)
        cout << "YES";
    else 
        cout << "NO";
    
    return 0;
}