#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 arr[10][10];
    bool hor = true;
    bool ver = true;
    for(int a0 = 0; a0 < n; a0++){
        int x;
        int y;
        cin >> arr[a0][0] >> arr[a0][1];
    }
    
    for(int i = 0; i < n-1; i++){
        if (arr[i][0] != arr[i+1][0])
            hor = false;
        if (arr[i][1] != arr[i+1][1])
            ver = false;
    }
    
    if (hor || ver)
        cout << "YES" << endl;
    else
        cout << "NO" << endl;
    return 0;
}