#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;
    if (n <= 1) {
        cout << "NO" << endl;
        return 0;
    }
    vector<int> x_arr(n, 0), y_arr(n,0);
    int x_base,y_base;
    cin >> x_base >> y_base;
    bool is_vertical = true, is_horizontal = true;
    for(int a0 = 1; a0 < n; a0++){
        int x;
        int y;
        cin >> x >> y;
        if (is_vertical && x != x_base)
          is_vertical = false;
        if (is_horizontal && y != y_base)
          is_horizontal = false;
        
    }
     
    if (is_vertical ^ is_horizontal)
    {
       cout << "YES" << endl;
    } else
    {
       cout << "NO" << endl;        
    }
    return 0;
}