#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 tmp_x, tmp_y;
    bool ok_x = true;
    bool ok_y = true;
    for(int a0 = 0; a0 < n; a0++){
        int x;
        int y;
        cin >> x >> y;
        if(a0 != 0){
            if(tmp_x != x)
                ok_x = false;
            if(tmp_y != y)
                ok_y = false; 
        }
        tmp_x = x; 
        tmp_y = y;
        
    }
    if(ok_x || ok_y)
        cout << "YES";
    else
        cout << "NO";
        
    return 0;
}