#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;
    bool xflag = 0;
    bool yflag = 0;
    int prevX;
    int prevY;
    cin >> prevX >> prevY;
    for(int a0 = 0; a0 < n; a0++){
        int x;
        int y;
        cin >> x >> y;
        
        if(prevX != x) xflag = 1;
        if(prevY != y) yflag = 1;
        
        prevX = x;
        prevY = y;
    }
    
    if(xflag && yflag) cout << "NO" << endl;
    else cout << "YES" << endl;    
    
    
    return 0;
}