#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 xPrev;
    int yPrev;
    cin >> xPrev >> yPrev;
    int xCur;
    int yCur;
    bool xLine = true;
    bool yLine = true;
    for(int a0 = 1; a0 < n; a0++){
        cin >> xCur >> yCur;
        
        if (xCur != xPrev) {
            xLine = false;
        }
        
        if (yCur != yPrev) {
            yLine = false;
        }
        
        if (!xLine && !yLine) {
            cout << "NO" << endl;
            return 0;
        }
    }
    
    cout << "YES" << endl;
    return 0;
}