#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;
    int fx,fy;
    bool tx = true, ty =true;
    for(int a0 = 0; a0 < n; a0++){
        int x;
        int y;
        cin >> x >> y;
        if(a0 == 0){
            fx = x;
            fy = y;
        }
        else{
            if(x!=fx){
                tx = false;
            }
            if(y!=fy){
                ty = false;
            }
        }
        if(!tx && !ty){
            cout<<"NO";
            return 0;
        }
    }
    cout << "YES";
    return 0;
}