#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 flagx = 0;
    int flagy = 0;
    int auxx,auxy;
    for(int a0 = 0; a0 < n; a0++){
        int x;
        int y;
        cin >> x >> y;
        if(a0==0){
            auxx = x;
            auxy = y;
        }
        else{
            if(x!=auxx){
                flagx = 1;
            }
            if(y!=auxy){
                flagy = 1;
            }
        }
    }
    if(flagx==1 && flagy==1){
        cout << "NO" << endl;
    }
    else{
        cout << "YES" << endl;
    }
    return 0;
}